Water Terminology

Acre-Foot (AF)
Unit of measuring a volume of water. An acre-foot of water is enough water to cover one (1) acre of land, one foot deep or 43,560 cubic feet. It is equal to 325,829 gallons.

Backflow Prevention Assembly
The term "backflow" means the undesirable reversal of flow of water or mixtures of water and other liquids, gases, or other substances, into the distribution pipes of the potable supply of water from any source or sources. A backflow prevention assembly is installed after the meter on the customer's side of the water system. It is a requirement of the State Health Department to prevent contaminants from entering the public water supply. All irrigation, commercial and industrial systems must be equipped with a backflow prevention assembly in accordance with the Uniform Plumbing Code (UPC).

Billing Deposit
All customers requesting a service installation of 1 ½" or less, who have not been able to establish their credit worthiness, as determined by Western, must post a cash deposit. This deposit is equal to an average of the previous twelve monthly bills for a service that is similar in use and size, but not less than $50.

Brine
Low Biological Oxygen Demand (BOD), Low Suspended Solids (LSS), and pH balanced wastewater containing non-toxic salts.

Commercial and Industrial Added Facility Charge (AFC)
AFC is collected from each new service based on meter size and pressure zone.Commercial and industrial services require an additional charge per acre to cover fire flow requirements due to the higher fire flow requirements for industrial and commercial land uses.

Equivalent Dwelling Unit (EDU)
Used to determine system demand for water facilities. EDU is one single-family residence. Per Western's design manual, which follows American Water Works Association (AWWA) standards, this is based on consumption of 300 gallon per capita per day (GPCD) with 3.8 residents per house for 1,140 GPD/unit.

Flow Rate
A measure of the volume of water moving past a given point in a given period of time.

Hot Tap
A connection made to an active, (live) pipeline for a water service connection, fire hydrant or connecting a newly constructed pipeline to an existing water pipeline.

Improvement District
Soon after Western was formed in 1954, it became necessary to construct facilities to distribute water. Improvement Districts were formed over different portions of Western's retail service area so bonds could be sold to fund the needed facilities. In order for a property to receive retail water service from Western, the property must be located within an Improvement District or it has to be annexed to the Improvement District.

Industrial Brine
Liquid brine (salt water) generated by an industrial process that cannot be discharged in the domestic sewer system. Generators of this type of waste may discharge directly to the Santa Ana Regional Interceptor (SARI) line via a direct connection. If the amount of waste generated is minimal or if the distance from the facility to the SARI line is too far, the generator may obtain a permit to haul by tanker truck and discharge at a designated dump station.

Pressure
The amount of force acting (pushing) on a unit of area. Usually expressed in pounds per square inch (psi).

PSI
A measurement of pressure. Pounds per square inch.

Santa Ana Regional Interceptor (SARI)
The Santa Ana Regional Interceptor (SARI) is a pipeline that was constructed to protect the Santa Ana Watershed from desalter concentrate and various saline wastes generated from industrial facilities. The SARI pipeline discharges to a treatment plant in Fountain Valley operated by the Orange County Sanitation District. The industrial waste is treated for the purpose of producing reclaimed water. The residual concentrated brine left over after the treatment process is discharged to the ocean.

Santa Ana Watershed Project Authority (SAWPA)
SAWPA is the agency that develops long-range plans for managing, preserving, and protecting the quality of water supplies in the Santa Ana Watershed. SAWPA is formed of five water and wastewater service providers. The five agencies are: Western Municipal Water District (WMWD); Inland Empire Utilities Agency (IEWA); Eastern Municipal Water District (EMWD); Orange County Water District (OCWD); and San Bernardino Valley Municipal Water District (SBVMWD).

Sewer Service
Western operates sewer collection systems and treatment facilities for the benefit of its customers.

Standby Charge
Each parcel within Western's Improvement Districts is assessed with a standby charge or water availability charge. This charge is assessed on each parcel, with or without water service. The fee is charged to parcels within an Improvement District with the justification that the water is "available" to them. This fee is an assessment and is collected through property taxes.

Unit
A unit is 100 cubic feet of water that is equal to 748.8 gallons.

Western Municipal Water District's Landscapes Southern California StyleSM
Landscapes Southern California StyleSM is a one-acre water conservation demonstration garden for the public and is located adjacent to Western's headquarters building. The garden is designed to encourage public acceptance, desire for, and use of water-efficient landscapes. To assist developers in meeting the City and County of Riverside's water-efficient landscape requirements, Western offers its Landscapes Southern California StyleSM water conservation pamphlets free-of-charge for display in the model homes and for distribution to new home buyers.

Will Serve Letter
As part of the land development process, this letter is a requirement by the County Department of Health Services committing Western to having the water available when the land division is complete.