Water Efficiency

1. Sustainable Sites

2. Water Efficiency• Goals / Overview• LEED NC Prerequisites & Credits

• Intent & Strategies• LEED EB O&M Credits

• Intent & Strategies

3. Energy & Atmosphere

Session 2: Agenda

Water Overview

Using large volumes of water increases maintenance and life-cycle costs for building operations and increases taxpayers costs for additional municipal supply and treatment facilities.

Mt Eriama Water Treatment PlantBolivar Waste Water Treatment Plant

Water efficiency measures in commercial & residential buildings can easily reduce water usage by more than 30% or 40%.

Tips from the Pros

In a typical 100,000-square-foot office building, low-flow fixtures coupled with sensors and automatic controls can save a minimum of 1 million gallons of water per year, based on 650 building occupants each using an average of 20 gallons per day.

Water Use Statistics• US daily consumption is approximately

340 billion gallons of fresh water per day. Annually we extract 3,700 billion gallons more water than we return to the natural water system.

• The UN reports that human water consumption has increased 6 fold in the last century, which is double the rate of population growth. This has resulted in estimated extinction of 20% of fresh water species.

Endangered Humpback Chub – Colorado River Basin

LEED Credits - Water Efficiency

WE P1 Water Use Reduction, 20% reduction Req’d

WE C 1 Water Efficient Landscaping, Option 1 Reduce by 50%, Option 2 (In addition to option 1) No potable use or no irrigation

2-4

WE C 2 Innovative Wastewater Technologies 2

WE C 3 Water Use Reduction, 30% reduction 2-4

Water Use Reduction, 35% reduction

Water Use Reduction, 40% reduction

LEED New Construction 1 Prerequisite, 10 points

LEED Credits - Water Efficiency

WE P1 Water Use Reduction, 20% reduction Req’d

WE C 1 Water Efficient Landscaping, Option 1 Reduce by 50%, Option 2 (In addition to option 1) No potable use or no irrigation

2-4

WE C 2 Innovative Wastewater Technologies 2

WE C 3 Water Use Reduction, 30% reduction 2-4

Water Use Reduction, 35% reduction

Water Use Reduction, 40% reduction

LEED for Schools 1 Prerequisite, 11 points

WE C 4 Process Water Use Reduction 1

LEED Credits - Water Efficiency

WE P1 Water Use Reduction, 20% reduction Req’d

WE C 1 Water Efficient Landscaping, Option 1 Reduce by 50%, Option 2 (In addition to option 1) No potable use or no irrigation

2-4

WE C 2 Innovative Wastewater Technologies 2

WE C 3 Water Use Reduction, 30% reduction 2-4

Water Use Reduction, 35% reduction

Water Use Reduction, 40% reduction

LEED Core and Shell 1 Prerequisite, 10 points

LEED Credits - Water Efficiency

LEED New Construction, Schools, Core and Shell

Referenced Standard: Energy Policy Act of 1992

It addresses energy and water use in commercial, institutional and residential facilities. This statute became law in 2005.

Water Efficient Landscaping

Water Efficient Landscaping

Intent:Limit or eliminate the use of potable water or other natural surface or subsurface water resources available on or near the project site for landscape irrigation.

Water Efficient Landscaping

Reduce potable water consumption for irrigation from a calculated mid-summer baseline case.

Water Efficient Landscaping

Reductions shall be attributed to any combination of the following items:– Plant species– Irrigation efficiency– Use of captured rainwater– Use of recycled waste water– Use of water treated and conveyed

by a public agency specifically for non-potable uses

Water Efficient LandscapingNo Potable Water Use or No Irrigation

• Use only non-potable water for total amount of water needed for irrigation through plant selection (except for initial watering to establish plants).

• Install landscaping that does not require permanent irrigation systems. Temporary irrigation systems used for plant establishment are allowed (if removed within 18 months of installation).

Tree gators are a non-permanent irrigation system that can help establish plants.

Tips from the Pros

Hose bibs for hand-watering may also be acceptable as non-permanent irrigation.

Water Efficient Landscaping

Potential Technologies and Strategies:• Perform a soil/climate analysis to design

landscaping with native/adapted plants to reduce/eliminate irrigation.

• Use high efficiency irrigation-Drip irrigation can use 30% less water than sprinklers.

• Zone irrigation based on terrain & vegetation.

• Use harvested building or storm water for irrigation.

• Use soil moisture tensiometers or rain sensors controls.

Water Efficient Landscaping

Variables used in calculations:

Landscape coefficient: Volume of water lost via evapotranspiration, depends on species, micro climate and planting density.

Species factor: Accounts for variation of water needs by different species rated by high average and low.

Water Efficient Landscaping

Density factor: The number of plants and the total leaf area of the landscape, sparsely planted areas have lower evapotranspiration rates than densely planted areas.

Microclimate factor: Environmental conditions specific to the landscape, including temperature, wind and humidity.

Water Efficient Landscaping

Evapotranspiration rate: he amount of water needed to grow a certain reference plant expressed in millimeters or inches.

Irrigation efficiency: Based on the type of irrigation used and the corresponding efficiency.

Review Question

A project practices water efficiency by reducing the potable water used

for irrigation by 50%. How could the project achieve additional water

efficiency?

A project practices water efficiency by reducing the potable water used for irrigation by 50%. How could the project achieve additional water efficiency?

Answer: Either eliminate the need for irrigation altogether OR use only non-potable water.

Review Question

Intent:Reduce generation of wastewater and potable water demand, while increasing the local aquifer recharge by:

• Reducing the use of potable water for building sewage conveyance.

• Treat of wastewater onsite to tertiary standards. For LEED, treated water must be infiltrated or used onsite.

Innovative Wastewater Technologies

Potential Technologies & Strategies

To reduce use of potable water:• Specify high-efficiency fixtures and

dry fixtures such as composting toilets and waterless urinals,

• Harvest stormwater or building greywater (sinks, showers) for sewage conveyance.

Innovative Wastewater Technologies

To treat wastewater onsite:• Implement on-site

wastewater treatment systems (constructed wetlands, high efficiency filtration system, living machines).

Potential Technologies & Strategies

Innovative Wastewater Technologies

Living Machines: Whole systems approaches to treating wastewater. They are accelerated versions of the water treatment facilities, incorporating helpful microbes, plants, snails and fish into diverse, self-organizing and responsive communities. Living machines are site-specific, biological solutions that re-route waste streams into resources.

Ben & Jerry’s

Innovative Wastewater Technologies

Water Use Reduction

Intent:Maximize water efficiency within buildings to reduce the burden on municipal water supply and wastewater systems.

Achieve (in comparison with a baseline set for the project) through high efficiency flow and flush fixtures per the Energy Policy Act of 1992.

EPAct regulated fixtures include lavatories, toilets, urinals, showers and kitchen sinks.

Projects can achieve up to 40% water usereduction without occupants even noticingthey are using “high efficiency” fixtures.

Specify fixtures to meet the following criteria:

• Lavatories – 0.5 GPM aerators and auto on/off set to 12 sec (rather than baseline 2.5 GPM).

• Urinals – 0.5 GPF or 0.125 GPF(rather than baseline 1 GPF).

Water Use Reduction

• Toilets – 1.2 GPF (or dual-flush) (rather than baseline 1.6 GPF).

• Kitchen Sinks – 1.8 GPM (rather than baseline 2.5 GPM).

• Showers – 1.5 to 1.8 GPM (rather than baseline 2.5 GPM).

Water Use Reduction

Process Water Use Reduction

Water-using systems other than lavatories, toilets, urinals, showers and kitchen sinks are considered “process water.”

Examples of process water use include:• Clothes washers• Dishwashers with racks• Cooling towers• Ice machines• Industrial processes

Definitions:

Potable water• Water suitable for drinking. Meets or exceeds EPA

standards.

Greywater• Multiple definitions (Uniform Plumbing Code,

International Plumbing Code, State and local codes)“untreated household waste water which has not come into contact with toilet waste.” (UPC)

Tips from the Pros

Blackwater • Does not have one widely accepted definition.• State and local codes may consider wastewater

from kitchen sinks, showers or bathtubs as blackwater.

• Wastewater from toilets is always considered blackwater.

Tips from the Pros

Integrated Water Management

Can the design process be integrated?

VS.

$

LEED Credits – Water Efficiency Existing Buildings Operations & Maintenance1 Prerequisite, 14 points

WE P1 Minimum Indoor Plumbing Fixture and Fitting Efficiency

Required

WE C 1 Water Performance Measurement 1-2

WE C 2 Additional Indoor Plumbing Fixture and Fitting Efficiency

1-5

WE C 3 Water Efficient Landscaping 1-5

WE C 4 Cooling Tower Water Management 2

EBOM: Water Use

Minimum Indoor Plumbing Fixture and Fitting Efficiency

Intent: To ensure that the building seeking certification has reached a certain level of water efficiency.

Requirement:Reduce fixture potable water usage to a level equal-to-or-below the water baseline, which is a percentage of the water usage.

Divides plumbing systems into 2 groups:•Completed in 1994 or later •Completed before 1994Uniform Plumbing Codes (UPC) 2006 or International Plumbing Codes (IPC) 2006.

Water Performance MeasurementIntent:To inform decision making regarding operations and retrofits by measuring water consumption.

Requirements:Have permanently installed water meter(s) measuring total potable water use (entire building and grounds). Data should be recorded regularly and summarized monthly and annually.

Strategies:Have a building wide water meter or series of water meters measuring all water delivered to the building.

Water Performance MeasurementRequirements:Have in place permanently installed metering for one or more of the following subsystems:

• Irrigation• Indoor plumbing fixtures• Cooling towers• Domestic hot water• Other process water

Additional Indoor Plumbing Fixture and Fitting Efficiency

Intent:To further increase water efficiency in existing buildings.

Strategies:Retrofit with high-efficiency fixtures:• Lavatories • Urinals – 0.5 GPF or waterless• Toilets – dual flush• Kitchen Sinks• Showers

Water Efficient LandscapingIntent:To reduce the consumption of water needed for landscape purposes.

Strategies:• Replace existing vegetated species with native, adapted, and drought

resistant varieties.• Install moisture meters around the soil to inform watering schedule.• Remove irrigation system (hand watering is allowed).

Cooling Tower Water Management

Intent:To ensure that the building management team is aware of the proper operating procedures required to maintain a cooling tower.

Cooling Tower Water Management

Requirements:Chemical ManagementImplement a water management plan for the cooling tower that addresses chemical treatment, bleed-off, biological control and staff training as it relates to cooling tower maintenance.

Water Management

Improve water efficiency by installing & maintaining a conductivity meter and automatic controls to maintain proper concentration.

Cooling Tower Water ManagementIntent:To further reduce potable water consumption during cooling tower operation.

Requirements:Use cooling tower makeup water from non-potable sources.

Examples of nonpotable water sources: stormwater, air-conditioning condensate, swimming pool filter backwash, cooling tower blowdown, pass-through cooling water, recycled treated wastewater, municipally reclaimed water.

Questions on Water Efficiency?