domestic and fire protection water supply and distribution...

Domestic and Fire Protection Water Supply and Distribution Systems

Susanne Cordery-Cotter

Carol Dollard

Sponsored By

Domestic and Fire Protection Water Supply and Distribution Systems Copyright APPA 2009

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Domestic and Fire Protection Water Supply and Distribution Systems

Introduction

A college or university must provide potable water and manage its water distribution system to serve hundreds to thousands of people each day. Those that do notown and operate the water distribution system serving their facilities should work closely with their water purveyor to ensure that reliable water of high quality isdelivered to their facilities. The water quality must meet regulatory limits and must be aesthetically pleasing.The potable water will be used for drinking, but it mayalso serve a plethora of other uses such as research, instruction, cleaning, irrigation, animal husbandry, and fire protection. Many universities use nonpotable waterfor irrigation and other applications as well. This chapter addresses some of the issues and topics encountered when a typical university supplies safe and pleasantwater through its potable water utility.

The major elements of water supply are the water source, treatment facilities, storage systems, and the distribution system. A small college or university in a ruralsetting may be responsible for all of these aspects of water supply, including identifying and caring for the source. However, most colleges or universities are locatedwithin a municipality or water district that supplies treated water to their distribution system; therefore, the distribution system is the focus of most universities'potable water utility.

In this chapter we briefly address the source, treatment, and storage system elements of water supply and provide a more in-depth discussion of distribution systems.We also touch on some unique aspects of small systems. The final part of this chapter addresses regulatory requirements applicable to safe drinking water.

Water Source

Water sources are generally divided into two types: surface water and groundwater. Surface waters include lakes and rivers. Groundwater is usually pumped up fromdozens to hundreds of feet below the ground surface. A third water source category includes "groundwater under the influence of surface water", which is shallowgroundwater or a spring that is subject to surface water intrusion or contaminant migration from the surface.

Treatment Facilities

The size and source of a water system dictate the type of treatment required. The smallest and simplest systems require disinfection as a minimum treatment. If thesource is surface water or groundwater under the influence of surface water, then filtration may also be required. Larger systems must implement treatment thatmeets turbidity requirements and contaminant levels and includes disinfection. Complex water treatment systems may consist of numerous unit operations, frombasic multimedia filtration to ultrafiltration or reverse osmosis.

It is important for system operators to have a basic understanding of where their water comes from and how it is treated so that if problems arise, the situation can beassessed and addressed efficiently. Municipal water treatment operators are typically eager and available to provide tours of and information about their treatmentfacilities to college and university facilities personnel. Getting to know the personnel at your local water utility and learning what resources they have available isalso valuable in the event of an emergency situation (such as a water main break or cross-connection).

Storage Systems

Areas with relatively flat topography may need elevated tanks in order to consistently get sufficient water pressure. These water towers provide additional benefits,including balancing the supply over daily variations in consumption patterns or extreme consumption such as fire fighting. The towers continue to provide water for aperiod of time if there is a pump failure or power outage. One of the significant benefits of water storage tanks is that the system pumps can be sized to meet lowerflow volumes. This is because during times of high demand, tank levels can be drawn down. However, operators must watch the "residence time" in these tanks sothat water quality does not deteriorate substantially. These facilities need regular maintenance, including painting (both inside and out), periodic disinfection, andregular checks to ensure that all vent screens are intact.

In addition to storage tanks that might serve a whole campus, it is common to have booster pumps and storage tanks on buildings too tall to be served by streetpressure. Static pressure losses accrue at 0.433 psi/foot, so there is a loss in static pressure of about 5 psi for each story in a multistory building. Most fixtures requirepressures in the range of 25 to 35 psi in order to function properly. If a booster pump is used in a building with fire sprinkler protection, backup generation isrequired so that fire sprinklers can still operate in the event of a power failure.

Fire Protection

Campus fire protection is generally part of the domestic water distribution system. Fire flow requirements for each building include many factors such as occupancyload, size of building, construction materials, and usage. The state fire marshal and local fire protection districts set fire flow requirements or necessary fireprotection measures for each building on campus. Typically, fire flow requirement for campus facilities vary from 1,500 to 3,500 gpm at 20 psi residual pressure.

Distribution Systems

Design

Piping Networks

Some of the earliest water systems in the United States were constructed using wooden water mains; however, cast iron, steel, and copper were the standard for thesesystems for much of the 20th century. Recently, advances in plastic pipe (high-density polyethylene, or HDPE, for example) have brought more of this type of pipeinto water utility systems. Plastics have some significant advantages in weight and cost, but there are some issues with pressure ratings, and none of these pipes havebeen in the ground long enough for us to really understand the longevity of these systems. While many of the plastic pipe materials appear to have good long-lifecharacteristics, connections may have less reliability.

When designing water distribution systems on campus, it is important to analyze the criticality of water supply to each building type. While the loss of water supplyto a classroom or office building could be merely an inconvenience, the loss of water supply to laboratory or animal care facilities for even a relatively short periodof time could endanger critical research. In addition, those buildings that on the surface do not appear to have critical water need may have HVAC equipment like aboiler or cooling tower that rely on makeup water. Should a water outage render those pieces of equipment inoperable, the building may no longer be habitable.

Once these critical loads have been identified, the water system can be designed (or upgraded) so that the systems are looped and water can be fed to criticalbuildings from a variety of sources. A critical element of a looped system is providing a sufficient number of valves so that sections of pipe can be isolated for repairand maintenance without impacting water service. Typically, there should be a valve on each leg at each pipe intersection (three valves at a "T" and four valves at across) and valves on every building service. However, you can get away with fewer valves if there are several pipe intersections in close proximity. The best test is tostudy water system maps and perform "what if"? analysis on the building impacts of water main breaks or repairs. If a particular section of pipe will "take down" several buildings in the event of a failure, analyze how to retrofit valves into the system in order to minimize the impacts. Radial feed legs within the water system


should be minimized due to reliability concerns.

In addition, it is critical to minimize "dead legs" in the water distribution system. Dead legs are created when there is a long radial feed to a seldom-used load. Firehydrant legs are a common culprit, but old feeds to abandoned facilities are sometimes cut off at the building rather than at the main, causing a dead leg that cancreate water quality problems in the system. The water in these dead legs is stagnant, and fluctuations in pressure and flow effect can draw some of this bad waterback into the water mains, causing water quality issues.

There is a downside to looped water distribution systems. Water will always follow the path of least resistance, so if there are different pipe sizes in the waterdistribution system, the water flow in the smaller pipes will be low. This can lead to water that has too long a residence time in the system, resulting in a degradationof water quality. In extreme cases, some of these smaller pipes can act almost as dead legs, leading to severe water quality problems. If there are a variety of pipesizes in a looped distribution system, regular flushing can help alleviate these water quality concerns.

Additional design efforts should be put into minimizing pressure drops in the system. Most utility systems provide water at 50 to 80 psig. If the water is outside thatrange, efforts must be made to correct the situation. If the pressure is too high, a pressure-reducing valve (PRV) must be installed at the building entrance. If thepressure is too low, a booster pump and pressure tank are usually required. Note that providing a looped system will not usually help low water pressure problems;however, it can improve water flows in systems with marginal pressure.

Conservation versus Quality

Water conservation measures are an important aspect of a sustainable future, especially in arid areas like the western United States where the scarcity of waterbecomes the primary topic of conversation in drought years. However, drinking water contaminant levels are concentration-based; therefore, when more water (i.e.,less conservation) is moving through a distribution system, it is more likely that the water quality will meet applicable limits. Another incentive to move largequantities of water is to prevent the water from stagnating in pipes, where it can pick up rust and other contaminants that may not represent a health threat but makethe water unpleasant to taste.

Historically, water distribution systems have been designed to provide more than adequate flow capacity for the largest demand, which is fire flow. This can result inmains and service lines that are oversized for most of their use, which is the demand in the building, resulting in stale water that may be warm or bad-tasting andpotentially contain disinfection byproducts.

Implementing conservation practices while providing healthy and pleasant-tasting water is a balancing act. We must continually reduce a building's water demandthrough low-use fixtures, laboratory modifications, and other conservation measures, but still ensure healthy and pleasant water. One way to understand the impactsof water conservation measures on the distribution system is to model the system and test different scenarios. These computer-based models are time-consuming toset up, but invaluable for testing out changes in the system before implementing them. Water modeling at Colorado State University, for instance, allowed utilityengineers to determine that a section of pipe with a failing water vault was not required to maintain adequate flows in the system. As a result, an expensive repairwas avoided and the pipe section can be cut off from the system.

Operations and Maintenance

System Mapping

The importance of accurate distribution system maps cannot be overemphasized. Accurate maps provide

Effective distribution system operation and maintenanceMinimization of repeated mistakes (e.g., closing a service at an incorrectly shown location)An effective planning tool for replacement and rehabilitation programsIdentification of water quality problem areasA basis for modeling

Water System Mapping showing domestic water distribution lines, fire lines, pipe sizes, and fittings.

The following topics should be considered as the system maps are developed or upgraded:

Valve locations: These are important in times of emergency, such as main breaks. They are also important for planning unidirectional flushing, systemreplacement, and upgrades.Main locations, size, and material: A pipe's size and material can affect flow and pressure characteristics at the delivery points. Accurate size and materialinformation helps troubleshoot flow and pressure problems.Age of the pipe: Pipe age is helpful in water quality and flow modeling and helps guide replacement and repair programs. It also provides necessaryinformation to help you comply with water quality testing regulations of contaminants such as lead and copper.Locations and dates of breaks: This information is needed for system replacement and rehabilitation planning.Locations and dates of complaints: This information is needed for system evaluation, replacement, and upgrade planning.

Mapping can be performed using AutoCad software, GIS software or both. If both are used it is important to have a process for establishing one type of software asthe master, with the other being updated promptly after changes are made to the master.


Symbols for valves, fire hydrants, meters and backflow preventers can be standardized using symbol libraries provided with the software, or developing user-specificsymbols. Pipe and fitting symbols are less universal today than they were a decade ago, therefore it is helpful to provide a legend for the map users. Typically, eachvalve is assigned an identifier and shown on the map at its actual location relative to buildings and other permanent objects. Other information about the valve, suchas direction of closure and gps coordinates, might be embedded in the map at the valve location.

Methods of locating valves in the field vary depending on the resources available to the user. A user might query the map electronically at his or her computer todetermine relevant distance to the valve from fixed objects, mark these on a to-scale printout and take it to the field as an aid in finding the valve. Utility locatingequipment and a metal detector can help pinpoint a valve box lid that has been buried.

Mapping is typically an ongoing process and relies on field measurements and observations to develop accurate and to-scale maps that are useful electronically aswell as in hardcopy format.

Leak Detection

Water leaks often account for a substantial portion of lost revenue in water utility systems. If you have a campus that either treats its own water or purchases water atthe campus boundaries and maintains a distribution system, water leaks are a direct revenue loss to the water system. For example, if 5 percent of the water in theColorado State University water distribution system were lost to leaks, it would be at a cost of over $100,000 per year.

A wide variety of strategies and technologies can be used to pinpoint leaks. These include water balance comparing submeter to master meter usage, fieldobservations, and a variety of listening devices. The effectiveness of these strategies is related to the pipe material in your system, depth of installation, soil type,and so on. Often a preventive maintenance (PM) program of actively monitoring water mains to find and repair leaks can pay for itself with the water saved. Ifresources are not available, or if the system is not owned by the university, a PM leak detection program may not be cost-effective. However, in order to preserveand protect the integrity of their system, water utilities often provide this service for little or no cost.

Flushing

Rust, tuberculation (deposits of corrosion products), sediment deposition, and slime growth are aspects of pipe deterioration and stagnant water that can result inpoor water quality. Periodic water main flushing using system hydrants helps to remove these impurities and improve flow. The frequency of flushing may varyfrom three times per year to once every three years, depending on the system's age, configuration, and condition. Areas of the distribution system with longdead-legs or low water usage may require more frequent flushing than other areas.

View a video of a hydrant being flushed.

System-wide flushing should be "unidirectional" to the extent possible, where the water is flushed from one end of the system to the other. This helps to increasewater velocity in each main and helps to prevent moving "dirty" water through or past segments previously flushed. Unidirectional flushing is accomplished byclosing select valves to force water along a chosen main in a specified direction. During flushing, the goal is to achieve a velocity of 5 feet per second (at a minimum,the velocity should exceed 2.5 feet per second) in each main. Each hydrant should be flushed until chlorine and turbidity are within specified parameters. Thechlorine and turbidity limits may depend on the supplier's normal disinfection rates and system age. An example of the flushing goals follows:

Chlorine : at least 0.5 mg/LTurbidity : below 3 NTU (nephelometric turbidity units)If parameters are not achieved, flush for no more than 15 minutes per hydrant.

Left: Sampling a fire hydrant during unidirectional flushing. Note diffuser and safety cones. Right: Measuring pressure during unidirectional flushing.

A system-wide flushing effort may take several weeks and requires planning and coordination. The following activities should be considered for a comprehensiveflushing program:

Coordination with the wholesale supplier: Unidirectional flushing can dislodge materials in the mains that may appear in customers' water in another location.If flushing with the wholesale supplier is not concurrent, it is important to notify the wholesale water purveyor so that it can be prepared to respond to anycomplaints.Notification to all system users: This may take the form of a mailing or campuswide e-mail. A sample notification paragraph is shown in Exhibit A.Special notification and coordination with sensitive users such as hospitals and dialysis patients.Preparation of equipment for each crew, including diffusers, safety cones, dechlorination equipment, sampling kits, and valve keys.Compliance with any dechlorination requirements: These may be imposed at the state level by the environmental agency having jurisdiction over surfacewater discharges. Requirements may vary from no action required to dechlorination at every fire hydrant.Mapping of each area with valve closures planned out in advance.

Once the flushing program has been planned, each flushing crew should follow the same procedures, which may include the following:

Plan the days flushing with an effort to minimize customer disruption.1.Notify any "critical" customers that may need to turn off sensitive equipment.2.Close requisite valves slowly to avoid water hammer.3.Mark closed valves on map as they are closed.4.Set up at hydrant with pedestrian, bike path, and traffic protection (cones, flaggers, etc., as appropriate).5.Open fire hydrant for flushing slowly, to avoid water hammer. View video.6.During flushing, watch for flooding or erosion.7.Sample at start and every five minutes. Observe quality periodically (Styrofoam cup works best because white cup allows for easy visual inspection forparticulates).

8.


http://www.youtube.com/watch?v=besQaww2urA

http://www.youtube.com/watch?v=nysWlCA9jco

Checking water quality. Sample and check visually and by testing every five minutes.

Document flushing information.9.Cease flushing if system pressures drop below 20 psi or clogged catch basins cause flooding or erosion.10.When the goals are met, close fire hydrant slowly to avoid water hammer.11.Open the closed valve and mark each on the map (or erase "closed" marks made earlier) as it is opened.12.

View video on chlorine testing of water sample.

A sample flushing documentation sheet is included as Exhibit B. One sheet per hydrant being flushed should be used.

During flushing, care should be exercised in the operation of fire hydrants. To avoid water hammer, the hydrant should be opened slowly; likewise, when closing ahydrant, the last several turns should be very slow. One instance of rapid fire hydrant closure at a university resulted in water hammer causing a five-foot longitudinalbreak in a 40-year-old cast iron water main that was otherwise in excellent condition. A dry barrel hydrant should always be opened fully, not partially, so that it doesnot saturate or erode the dry well at the base and drains properly when closed.

Operations and Maintenance

Disinfection

Water mains should be disinfected according to the American Water Works Association (AWWA) Standard for Disinfecting Water mains (C651-05). The AWWAstandard allows three options for superchlorinating the pipe and fittings:

Continuous feed (25 mg/L, 24-hours contact time)1.Tablet (25 mg/L, 24-hours contact time)2.Slug feed (100 mg/L, 3-hours contact time)3.

The most common method appears to be option 2, where tablets are taped inside the pipe sections during installation and the pipe is filled with water and allowed tosit for 24 hours before flushing and testing.

The steps for disinfecting a new main and fittings are as follows:

Superchlorinate piping and fittings (25 mg/L if tablet method).1.Allow to set for 24 hours (contact time).2.Dechlorinate, by discharging to pre-planned location3.Flush to background chlorine concentration (approximately 0.5 mg/L).4.Measure chlorine before and after.5.Collect sample for bacteriological analysis (coliform).6.Review results, usually available after 24 hours.7.If "negative" result (i.e., no coliform present), okay to activate new piping.8.

Step 3 requires coordination between the facilities personnel and the contractor conducting the work. The superchlorinated water cannot be directly discharged tostorm systems or waterways. Contractors are often conservative in their preparation of the superchlorinated water, resulting in chlorine concentrations far in excess ofthe 25 mg/L required by the standard. Concentrations may range from 50 mg/L to 2,000 mg/L. The facilities personnel and contractor must plan a dechlorinationmethod or a discharge location that is appropriate for the superchlorinated water. Options may include the following:

Containerize the water and add vitamin C or other dechlorinating chemical before discharge to storm systems,Discharge to an above-ground earthen pond that will not directly discharge to storm systems, orDischarge to the sanitary sewer with permission from the local publicly owned treatment works (POTW).

The volume of water to be handled depends on the pipe size and length and on the initial superchlorination concentration. When planning the discharge, rememberto account for the initial pipe volume plus an additional two or three pipe volumes for concentration reduction. When the concentration is reduced to the potablewater supply concentration, discharge can be in accordance with local or state discharge of potable water requirements.

Exhibit C is an example of a form that facilities personnel can provide to contractors to use for pipe disinfection activities.

Complaints

Distribution system operators' primary responsibility is the delivery of safe and pleasant water. All customer complaints should be taken seriously andaddressed promptly. Complaints may come via phone or e-mail or in person to any of the facilities personnel. The complaint may be delivered in acourteous fashion or with frustration. Regardless, the person receiving the complaint should listen and indicate what steps will be taken. There shouldbe a procedure for conveying the complaint to an appropriate person at facilities, investigating, and following up.

Complaints about poor water quality are sometimes ambiguous, and the system operator must take time to interview and understand the customer'sconcerns. Each complaint must be investigated to determine whether the water quality represents a health threat. Investigative work might include

Interviewing building occupants (in person or via e-mail)Sampling for suspect impurities or pollutants (e.g., coliform, copper, iron)Flushing hydrants and/or plumbing fixtures to attempt to isolate the location of the problemObserving the water's appearance at different times, such as after a break or holiday weekendEvaluating utility and building plumbing systems through drawings review

The follow-up work will depend on the nature and cause of the poor water quality. It may entail simple steps such as explaining analytical information or changingout a plumbing fixture, or it may require complex steps such as relining service lines or altering the characteristics of the water entering a building. The type of solution will beunique to each situation.


http://www.youtube.com/watch?v=FpyO8Q1aBUs

Exhibit D is a sample complaint tracking form that can be used for each customer complaint received.

Complaint dates and types can be included as a layer in the utilities mapping effort. Mapping the location and date of each complaint can help elucidate patterns indicating distribution system problems.

Metering

Though it depends on the cost of water in the area, typically, obtaining water meter data down to at least the building level is a sound investment for an institution.Detailed water consumption data are important to identify problems in individual buildings. In addition, individual building totals can be compared to master metersin order to identify leaks in the distribution system. Of course, reading and logging the data on a regular basis is an ongoing expense; however, utility databasesoftware can help manage the task.

An example of how metering can be useful: One university's equine facility had horse waterers, and a leak developed in one of the underground lines serving them.The ground was shale in that area, so the water disappeared underground and there was no trace of the leak at the surface. When the monthly reading for the buildingsubmeter came in hundreds of thousands of gallons above normal, an investigation began that led to the discovery of the problem. If there had not been a buildingsubmeter, the leak would have gone undetected in the noise of the much larger campuswide master water meters and could have continued for months or even years.

Some universities are utilizing real-time metering, which provides nearly instantaneous feedback on utility use. If the data can be managed and appropriate "alarm"levels established, these metering systems can be quite valuable in quickly pinpointing problems in the system. However, on many campuses, facilities staff isstretched too thin to set up, maintain, and monitor systems like this, thus limiting their value.

Certified Operators

Federal primary drinking water regulations (40 CFR part 141.130 (c)) require each state to develop and administer an operator certification program. Each watertreatment, storage, and distribution system must be under the supervision of a certified operator who is in direct responsible charge of the system. A certifiedoperator's primary objectives are

Ensuring that safe and pleasant drinking water is delivered to every system tapProviding adequate volumes and pressures for all uses, including fire fighting

To meet these objectives, the operator's responsibilities include

System operation and maintenanceSamplingRecord keepingTroubleshootingPublic relationsSafetyAdministration

States must keep a register of qualified operators who have met the state requirements developed under S.142.16(h)(2). A certified operator program typically hasdifferent levels and types of certified operators, each with a specific set of requirements and tests. For example, there may be four or more classifications of watertreatment facility operators depending on system type and size, and three or more classifications of distribution system operators depending on population served. Toevaluate the certified operator requirements appropriate for your system, visit your state's environmental agency Web page and contact the person in charge of yourstate's certified operator program, or the applicable EPA regional office, contact information for which can be found at www.epa.gov/epahome/regions.htm.

Note that the registration and scheduling for testing can be a lengthy process.

Emergency Preparedness

Threats and disasters such as terrorism, earthquakes, floods, fires, tornadoes, extreme weather conditions, and power outages are events for which water systemmanagers must plan. If the operational staff is not prepared to take necessary action to minimize the effects of such disasters, these problems may cause a greaterimpact in terms of loss of life and property.

Some of the most critical elements of a water distribution system during a disaster are storage, pumping, and the ability to deliver safe drinking water fromalternative sources. Earthquake-related emergencies are often followed by fire and power outages. Therefore, if a distribution system relies heavily on pumping, alack of electricity and a shortage of storage capacity could curtail or reduce the ability to fight a fire. It is important to have either diesel or natural gas generators torun engines as a backup to electricity.

Most institutions have a written emergency operations plan, one component of which should be the "who, what, when, and where" ? associated with the waterstorage and distribution system. Tabletop exercises, plan updates, and maps are important elements in any emergency management plan. At a minimum, theemergency operations plan should include

Vulnerability assessment resultsPhone numbers of personnel within the organization, local emergency officials, and state and federal agenciesOrganization chartRecovery to operations plan, which describes the steps for resumption of normal operationLocal and regional agencies such as water, health, police, and fireCommunications procedures

Once a crisis is under way, communication with the public and the media is crucial for effective management. Most educational institutions have progresseddramatically in the last few years to develop an incident response protocol and team, with directions on who contacts the media, when, and with what information. Ifprocedures for communications have not been planned, they should be considered and incorporated into the emergency operations plan.

The water system's integrity before and during a disaster must be evaluated and components adjusted as needed. The following are some evaluation tools:

Early detection and warning through real-time distribution system monitoring and surveillanceEmergency sampling kit holding sample containers such as HDPE bottles, 40 ml vials, and glass amber bottles; sampling may be needed at the incident site,with backup or duplicate samples, and at a background location

Cross-Connection Control

A cross-connection is a general term for when nonpotable water is introduced into the potable water system. It can cause contaminated water to mix with the watersupply and potentially cause dangerous conditions. It is the responsibility of the water purveyor (the university if it owns the distribution system, or the local waterutility) to ensure safe drinking water; therefore, that entity is usually responsible for minimizing the risks of cross-connections. While cross-connections directly tothe water utility do occasionally occur, most cross-connections occur through backflow events (backpressure or backsiphonage).

A back siphon occurs when there is low or negative pressure in the water distribution system. A classic example often seen on a university campus is a hose attachedto the faucet sink in a laboratory building. If that hose is lying in a sink filled with wastewater and a low-pressure event occurs in the local water system (a watermain break or hydrant being opened), that wastewater can be siphoned back into the potable water supply.

Backpressure, on the other hand, occurs when a nonpotable source is connected to the potable water supply and the nonpotable source operates at a higher pressure.For example, a greenhouse irrigation system might be connected to a nonpotable water supply in the summertime when it is available, but then operate on a potable


http://www.epa.gov/epahome/regions.htm

water supply in the winter when the untreated irrigation water is unavailable. If these systems are not properly isolated, the nonpotable supply could operate at ahigher pressure than the potable water system and there is significant potential for cross-contamination.

There are four types of backflow prevention (BFP) devices: vacuum breakers, double check valve assemblies (double check), reduced pressure (RP) backflowassemblies, and air gaps. An air gap is the simplest and most reliable BFP device, but it is not practical in all applications. What type of BFP device is called for ineach situation is a function of level of potential hazard (how easy would it be for that device to backflow into the water supply?) and the potential risk (what are thechances that a backflow event would affect the drinking water supply?). The local water purveyor will likely have regulations stating which situations require whichlevel of protection.

To protect the drinking water supply from cross-contamination, it is important to look at the problem from a variety of levels. First identify potential sources(laboratories, boiler makeup, cooling tower makeup, etc.) and provide protection for the other occupants of that facility. Often an air gap can be used, but a testableBFP device may be required. The next level of protection is to provide a BFP device at the building entrance; this protects the buildings within the campus frombeing affected by any events in the adjacent buildings and protects the water main. Finally, the local utility may require BFP devices at all metering points, which ina master meter situation will result in BFP protection at the campus level.

Approved testable reduced pressure backflow prevention (BFP) devices (two in parallel to avoid disruption of water supply to building).

One additional level of protection, used in some high-risk buildings, is to have both a "potable" and "nonpotable" plumbing system within the building. The potablesystem serves kitchens, bathrooms, and drinking fountains areas where occupants are likely to drink the water. The nonpotable water would supply laboratory sinksand mechanical equipment. These two systems would be isolated with BFP devices (often an RP device) at the building entrance.

Maintaining BFP protection requires significant staffing resources. Both double checks and RP devices require annual testing and maintenance. During this testing,water has to be shut off. Because of this, Colorado State University chose to install two devices in parallel at each building entrance in order to avoid a water outagein the building (the devices can be isolated and tested independently). This greatly simplifies the testing procedure but doubles the number of devices that have to betested. At CSU, currently more than 700 BFP devices are being tested annually. Testing BFP equipment can have a large impact on maintenance budgets. Thetesting must be completed by certified operators. On large campuses, it is likely that in-house staff will retain this certification and conduct the testing.

One more thing to consider when designing for the installation of BFP devices: RP devices provide one of the highest levels of protection; however, they have thepotential to dump substantial volumes of water. There is a failure mode that could result in a continuous dump. As a result, it is imperative when installing thesedevices that adequate drainage be provided in equipment rooms and that floor drains are kept clear of debris. Another option is to install these devices outside so inthe event of a dump, they can drain harmlessly outside the building, but an RP device cannot be installed below grade, so in freezing climates they must be put ininsulated and heated boxes.

Backflow prevention devices located outside in hotbox to prevent freezing.

Reclaimed Water

Reclaimed water and gray water are all seeing broader consideration for use in irrigation, toilet flushing, and fire protection water systems. Some examples ofmethods and benefits are described in the following paragraphs.

Gray water used for toilet flushing and irrigation. Sink, shower, and laundry water can be collected, filtered, and reused for toilet flushing and irrigation. Thebenefits include conservation of treated water and lower utility bills.Reclaimed (treated) water in a separate system for fire suppression. Treated wastewater, while not typically suitable for reuse as potable water, can be storedand used for fire fighting.1 This requires a dual distribution system: one for potable water and one for fire flows. Benefits include smaller pipe diameters forthe potable system with lower cost and lower water age, resulting in fewer quality problems. Disadvantages include higher capital cost for dual distributionsystems.Reclaimed water injected for saltwater intrusion barrier. Treated wastewater can be injected in coastal areas to hold back saltwater threatening intrusion intodrinking water aquifers.

Dual systems can be used in buildings in accordance with the International Plumbing Code's (IPC) requirements. Piping used for recycled water must be purple incolor. Denver, Colorado, has a large-scale purple pipe distribution system that uses treated wastewater for industrial and irrigation applications.

Some communities with concern over cross-connections or backflow into potable systems still resist use of raw or gray water for irrigation systems. This underscoresthe importance of a robust cross-connection control system and diligence in testing and record keeping.

In addition to resistance by municipal suppliers, large hurdles to water reuse exist in some areas of the United States, including the barrier of water rights. InColorado, collection and reuse of any "single use" water or rainwater is prohibited by water law, and no de minimis amount of reuse is legally allowed. Gradualchanges to water law to allow more reuse are occurring; however, water rights in Colorado still represent a formidable obstacle to widespread and innovative reuse.

Other hurdles include public perception and concern with exposure to pathogens.


Other hurdles include public perception and concern with exposure to pathogens.

All types of water reuse systems can result in decreased volumes and commensurate water treatment costs for potable water. Although reduced treatment cost is nota direct benefit to purveyors such as colleges and universities that receive treated water from a municipality and do not directly incur treatment costs, the overallbenefits of water conservation and decreased treatment burden are advantageous on a regional scale and long-term basis. Further, educational institutions areexpected to be researchers and incubators of innovative measures and should lead by example.

Small Systems

The size and source of a water system dictates the type of treatment required. The smallest and simplest systems require disinfection as a minimum treatment. If thesource is surface water or groundwater under the influence of surface water, then filtration may also be required. Larger systems serving nontransient populations ofmore than 10,000 must implement treatment that meets turbidity requirements and contaminant levels and disinfects. Complex water treatment systems may consistof numerous unit operations, from basic multimedia filtration to ultrafiltration or reverse osmosis.

A small system has fewer sampling and analysis requirements than a large system; however, it must be managed just as diligently. Disease outbreaks have occurredin small systems and can be devastating from a human health impact and public relations standpoint. The following five main categories must be addressed in theadministration of a small water system:

Regulatory complianceWater resource managementTreatmentDistributionPersonnel

Most problems and the highest numbers of violations in small systems are associated with coliform sampling and data evaluation. Problems include noncompliancewith monitoring frequencies and incorrect data calculations.

Planning is a key element in small water systems management. There must be attention to regulatory compliance and funding for trained personnel, systemoperation/maintenance, capital improvements, infrastructure repair, and catastrophe response. A small system should have the following plans in place and regularlyupdated:

Monitoring planMaster planCapital improvement plan10-year financial plan

Most state environmental agencies have representatives designated to assist small systems. The regulators are invariably very helpful and usually more interested inbringing systems into compliance than in levying fines.

Regulations

Drinking water is regulated under the Safe Drinking Water Act (SDWA) of 1974, and its amendments. The federal regulations promulgated under the SDWA can befound in 40 CFR Parts 141, 142, and 143. Most states have been given primacy, and the state's environmental agency is the primary authority for enforcing thefederal regulations. The state regulations often closely follow the federal regulations.

Drinking water regulations govern treatment, monitoring, distribution, and reporting requirements. Specific safe drinking water regulations have been promulgatedfor a plethora of topics, including contaminant levels for dozens of constituents (including coliform, lead, and copper arsenic), surface water treatment, groundwater,filter backwash recycling, disinfection byproducts, radionuclides, public notification, standardized monitoring, variances, sampling requirements, analyticalmethods, laboratory certification, reporting, record keeping, notifications, certified operators, and small systems. The regulations run to hundreds of pages.

The following paragraphs provide brief summaries of some of the topics included in the federal and most state drinking water regulations.

Contaminant Standards

Contaminants in drinking water are regulated by standards set by the U.S. Environmental Protection Agency. Maximum contaminant levels (MCLs) are legallyenforceable limits that apply to public water systems. They can be grouped into six main categories:

MicroorganismsDisinfectantsDisinfection byproductsInorganic chemicalsOrganic chemicalsRadionuclides

Maximum contaminant level goals (MCLGs) are nonenforceable public health goals, below which there is no known or expected risk to health. Most of the primarydrinking water contaminants have an established MCL and a lower MCLG. One example is lead, which has an MCL of 0.015 mg/L and an MCLG of zero.

Secondary standards are nonenforceable guidelines regulating contaminants that may cause cosmetic effects such as skin or tooth discoloration, or aesthetic effects(taste, odor, or color) in drinking water. Secondary standards are nonenforceable recommendations. Individual states may adopt secondary standards as enforceablestandards, so it is always best to consult state-specific regulations in addition to federal regulations.

The following link provides the current MCLs, MCLGs, secondary standards, and unregulated contaminants for federally regulated drinking water contaminants:http://www.epa.gov/safewater/contaminants/index.html.

Monitoring and Analytical Requirements

Federal and state drinking water regulations provide specific requirements for contaminant monitoring, depending on the water system's source water, populationserved, and type of system (e.g., transient or nontransient). The regulations describe the types of analyses, frequency, and number of samples to be collected.Colleges and universities may be required to conduct their own monitoring if they are regulated by their state as a "consecutive system" or are a small system.System monitoring is required to be planned and described in a written monitoring plan. Analytical methods are specified and must be performed by laboratoriescertified in each method.

Reporting and Record Keeping

Reporting requirements include analytical reporting, consumer notification in case of a violation (violations are categorized depending on their severity), and annualconsumer confidence reports. Record keeping requirements are specified for various data collected during system monitoring; for example, bacteriological recordsmust be kept at least 5 years and chemical analyses at least 10 years.

Treatment Requirements

Federal and state drinking water regulations establish criteria under which filtration is required as a treatment technique for public water systems supplied by surfacewater or groundwater under the direct influence of surface water. Filtration to a specified efficiency is required in lieu of MCLs for turbidity and certain viruses andbacteria. Lead and copper are regulated through specified treatment or corrosion control requirements in addition to MCLs.


http://www.epa.gov/safewater/contaminants/index.html

bacteria. Lead and copper are regulated through specified treatment or corrosion control requirements in addition to MCLs.

Disinfectant Residuals and Byproducts

Disinfectant residual concentrations for systems required to filter are specified at the entrance to the distribution system and in the distribution system. In addition,chlorine has an MCL and cannot exceed 4.0 mg/L at the tap. Disinfection byproducts, including trihalomethanes and haloacetic acids, which may pose health risks,can be formed as a result of disinfectant (e.g., chlorine) reacting with naturally occurring materials in the water.

A helpful link to the federal regulations is http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?sid=989d6af613f1f1292f3d26b2468387b5&c=ecfr&tpl=/ecfrbrowse/Title40/40cfrv22_02.tpl. Scroll to Part 141 and Part142.

Another helpful link to evaluate how and when various rules apply to water systems is www.epa.gov/safewater/publicoutreach/quickreferenceguides.html.

Links to state regulations typically can be found on each state's environmental agency Web page.

Exhibits

Exhibit A. Sample Flushing Notification

FOR IMMEDIATE RELEASE

**Date**

Contact: Public Relations Manager

***Name, phone, e-mail***

***Utility Name*** Will Flush the Water Distribution System Beginning ***date***

Campus utilities crews will begin flushing the water distribution system ***date***, weatherpermitting, from 7 a.m. to 5 p.m., Monday through Friday, for approximately eight weeks.

During this process, fire hydrants are opened and water is flushed through at high speeds, cleaningthe pipes and removing the sediment that can affect the water's taste and color. Flushing is anessential preventative maintenance strategy for the water distribution system and helps maintainwater quality and keep our water fresh.

Flushing will begin between Overland ***describe location or streets where flushing will begin***and move eastward through campus, ending at ***end location***. Crews will work from the northto the south with ***name*** Street as the approximate northern boundary and ***name*** Streetas the southern boundary. Please be cautious of people working in the streets during this time andobserve traffic diversions.

Sometimes the sudden rush of water can stir up sediments in the pipes and cause the water tobecome cloudy or discolored. These sediments are not harmful, but they may effect experiments orstain laundry. If you experience cloudy or discolored water, wait until the nearby flushing iscomplete, remove any aerators or filters from your plumbing, and run your COLD water until itclears. This water can be used on plants or landscaping.

This process doesn't typically interrupt water service, but it can happen on occasion. A loss of waterpressure is more common.

For more information, view our frequently asked questions (FAQs) at ***provide websiteaddress***. You can also call or e-mail: ***contact person's phone numbers and e-mails****

Exhibit B. Sample Flushing Documentation Sheet

FLUSHING TEST FORM

CAMPUS

FLUSH AREANAME:

DATE CREW:

HYDRANT NUMBER


http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?sid=989d6af613f1f1292f3d26b2468387b5&c=ecfr&tpl=/ecfrbrowse/Title40/40cfrv22_02.tpl

http://www.epa.gov/safewater/publicoutreach/quickreferenceguides.html

HYDRANTINFORMATION

(YEAR,CONDITION)

FLUSH STARTEDAT: (DATE, TIME)

DRAINAGEISSUES

STATIC PRESSURE

FLOW RATE (IFMEASURED)

WATER LOOKSCLEAR AT (TIME)

TURBIDITY TESTS (SHOULD BEBELOW 3)

CHLORINE TESTS (SHOULD BEBETWEEN 0.2 AND 0.5)

TIME RESULT (NTU) TIME RESULT (MG/L)

GAVE UP ONTURBIDITY

GAVE UP ONCHLORINE

COMMENTS:

Flow rate provides useful information if no valves are closed. If valves are closed, flow rate may be measured butshould not be considered representative of hydrant's true capacity.

Exhibit C. Water Main Disinfection and Testing Form

COPY SENT TO:

H:\Utility\City Consecutive Water System\Disinfection and operator rqmts\[Water main disinf form REV D.xls]Disinfectionform CSU Project Manager's File:

Rev D CSU Utilities Services:

General Project Information:

Campus: Location: (attach a map)

Project Number: Date and Time:

Weather: Prime Contractor:

CSU Inspector: Subcontractor:

Water System Construction Information:

Water main length: (ft) No. of Valves:

Water main diameter: (in) No. of tees:

Pipe material: Water main volume (gal):

Disinfection Information:

Disinfection method: (check one) Time and date started:

Continuous feed (25mg/L, 24 hr contact time) Disinfection Contractor:

Tablet (25mg/L, 24 hr contact time) Chlorine measurement test method:

Slug feed (100 mg/L, 3 hr contact time) Disposal of superchlorinated water method:

Disposal method was approved by:

Disinfection Record: Flushing amount (gal):

Chlorine measurement (mg/L) Time Flushing water disposal location:

Chlorine concentration at beginning of flushing (mg/L)

Chlorine concentration at end of flushing (mg/L)

Bacteriological testing sample collection time:

Result:

Pressure Testing Record:

Gauge reading Time Gauge reading Time

Date:


Signature:

Exhibit D. Sample Customer Complaint Tracking Form

Complaint Information

Complaint Received By:

Date: Time:

Customer Filing Complaint:

Phone:

Address:

Nature of Complaint:

Additional Comments:

Investigation Information

Investigated By:

Date: Time:

Findings:

Corrective Actions Taken:


Follow-Up

Follow-Up By:

Date: Time:

Customer Contact:

Reviewed With Customer:

Notes

1. DiGiano, F. A. "Benefits of Shifting Fire Protection to Reclaimed Water." AWWA Journal, February 2009, 65-74.

Additional Resources

Dagostino, Frank, et al. Mechanical and Electrical Systems in Construction and Architecture. New York: Prentice Hall, 2005.

Water Distribution System Operation & Maintenance; Office of Water Programs, California State University, Sacramento, California, 2005.


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