CHARNOCK WELL FIELD

SANTA MONICA WATERTREATMENT PLANT

Filtration through a three-stage ReverseOsmosis (RO) membrane system softensthe water by removing minerals (calciumand magnesium). RO uses pressure to

force water through membraneswith pores so small the

minerals can’t passthrough.

Reverse OsmosisFiltration

Water Quality AdjustmentsThe mineral content is adjusted

to the desired softness. The pH is adjusted, fluoride is added and the water

undergoes final disinfectionwith chloramine.

Final DeliverySanta Monica residents and businesses receive water foreveryday use. Water conservation by end users is key to

ensuring water reliability and sustainability.

Aeration and StorageThe final step, aeration, uses the existing air stripping technology in the five million gallon

reservoir to remove anyremaining volatilegroundwatercontaminants such astrichloroethene (TCE).

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PretreatmentTo protect the sensitive Reverse Osmosis (RO) filters,the combined well flow is filtered again throughgreensand and cartridge filters to remove more ironand manganese and any remaining sediment.

S A N T A M O N I C A W A T E R T R E A T M E N T P R O C E S S

Charnock WellsGroundwater contaminated with thegasoline additive MTBE is pumped upfrom 400 feet below ground surface.

Greensand FiltrationThe well water is filtered through

greensand media to remove iron andmanganese which would foul the

carbon filters.

GAC FiltrationThe MTBE is removed by filteringthrough Granular Activated Carbon

(GAC) filters.

Pump to Treatment Plant The filtered water is combined with theflow of other wells and pumped to theSanta Monica Water Treatment Plant.

What is the Santa Monica Water Treatment Plant?The Santa Monica Water Treatment Plant was designedand built to treat water from the City’s groundwater wells,including those located at the Charnock Well Field. TheCharnock wells were shut down for more than 14 yearsdue to contamination with Methyl tert-Butyl Ether(MTBE), a gasoline additive leaking fromgas stations in the area that is now bannedin California. Before losing use of theCharnock wells, the City relied on the well field to meetabout 45% of its daily water needs. During the years thewells could not be used, almost 85% of the City’s dailyneed for water was met by purchasing imported water.The wells and new facilities at the Santa Monica WaterTreatment Plant began producing potable water againfor the City of Santa Monica on December 4, 2010.

How does the Santa Monica Treatment Plant work? Groundwater from the Charnock, Olympic and ArcadiaWell Fields is pumped from 10 water wells in and aroundSanta Monica. The wells vary in depth from 235 to 540feet and range in production capacity from 250 to 2,000gallons per minute (gpm). Water from the CharnockTreatment Unit is pretreated to remove MTBE beforebeing mixed with water from the other wells andpumped 3½ miles to the Santa Monica Water TreatmentPlant near the border of Santa Monica in West LA. Thisfacility provides additional pretreatment, filtration viareverse osmosis and aeration.

The treated water undergoes constant, rigoroustesting at the well field and the Treatment Plantby plant operators and staff of the City’s WaterQuality Laboratory. Permission and oversightto operate a community water system is

granted by the California Department of Public Healthand the U.S. Environmental Protection Agency. Santa

Monica has a perfect compliance record inregards to water quality. For questionsregarding water quality, call the WaterQuality Laboratory staff at (310) 826-6712 or visit the City’s water qualitywebsite at waterquality.smgov.net.

Does this water provide for all of Santa Monica’s needs? Currently, the City uses an average of 12 million gallons of waterper day (mgd). About 8 mgd comes from the Charnock wells,and the rest from the Olympic and Arcadia wells, 1.4 mgd and0.4 mgd respectively. The facilities completed at the SantaMonica Treatment Plant will provide for a final production totalof about 8½ mgd. Additional water needed to meet the City’sdaily needs will continue to be purchased from theMetropolitan Water District of Southern California untilsuch time as Santa Monica can become self-sufficientin its water supplies.

How reliable is this water source? How long will it last?The Charnock Well Field first began providing water to SantaMonica in 1924 and has since been the major source for theCity. The well water proved to be an extremely valuableresource after the Northridge earthquake in 1994 whenimported water to the City was unavailable for several days.The groundwater aquifer that is the source for the well field isnaturally replenished by rainfall from the nearby Santa MonicaMountains and surrounding area. Water can be drawn from thisnatural source in a sustainable way if the amount extractedeach year does not exceed the natural replenishmentrate. Managing groundwater sources in this wayshould ensure that the City can count on thisresource for future generations through the efficient

use of existing water supplies, and barring shifting precipitationpatterns due to global climate change. For now and into theforeseeable future, having this water supply makes the City lessreliant on other sources. The City makes every effort to protectthis supply and make it last through policies and practices thatencourage green building design and sustainable landscapingand irrigation practices, as well as encouraging simple dailyhabits by consumers to conserve water.

Who paid for the Santa Monica Water Treatment Plant? In 2006, Santa Monica reached an agreement with three majoroil companies responsible for the MTBE contamination torestore the Charnock Well Field so that it could once again bea viable drinking water source. City staff and a team of expertsconsisting of independent engineers, geologists, scientists andenvironmental contractors conducted studies to determine andimplement an optimum solution for treating the groundwaterproduced from the Charnock Well Field to ensure that all

drinking water regulatory requirements aremet now and for decades to come. Theselection of the state-of-the-art technology of ReverseOsmosis ensures that the City will enjoy additional waterquality benefits and added protection against potentialpollution in the future.The cost to restore the CharnockWell Field and to design and build the Santa MonicaWater Treatment Plant was $60 million, which was paidthrough a settlement agreement with the oil companies.

What other water facilities does the City own andoperate? The City of Santa Monica operates its municipal waterutility as a self-supporting enterprise. The utility serves89,000 residents through more than 16,000 serviceconnections. The utility maintains and operates 10groundwater wells, two imported water connections, twotreatment units, four storage reservoirs, two pumpstations, and 240 miles of distribution mains. RivieraReservoir is the City’s largest storage reservoir at 25million gallons. Additional reservoirs include the SanVicente, Franklin Hill, and Arcadia reservoirs with acapacity of 5 million gallons each.

Can I take a tour of the Water Treatment Plant? Tours are available by request only. To get moreinformation or request a tour, please call the TreatmentPlant staff at (310) 826-6712.

How can water users conserve water? The City of Santa Monica has a strong commitment toensure a safe and continuous supply of water for futuregenerations. Voluntary water conservation is one way tohelp safeguard the community’s water supply. Here somesimple tips to save water: (1) Convert sprinklers to dripirrigation or install a rain barrel. Rebates and grants maybe available. (2) Replace old toilets and clothes washerswith high-efficiency models. (3) Wash full loads of clothesand dishes. (4) Fix all leaking faucets, shower-heads, andirrigation systems immediately. (5) Take shorter showers.These are just a few tips. For more ways to conservewater and other sustainability tips visit the City’s Office of Sustainability and the Environment atsustainablesm.org/water.

S A N T A M O N I C A W A T E R T R E A T M E N T P L A N T F A Q s

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