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Water Glossary

Discover Common Water-related Acronyms, Definitions, and Units of Measurement


Advanced Metering Infrastructure

Automatic meter reading equipment 

Commercial, industrial, and institutional 

California Irrigation Management Information System, 

Evapotranspiration, water loss via evaporation from plant surfaces and soil at base of plant and transpiration from plant leaf or grass surfaces 

Reference ET for a standard crop of grass 4 inches to 7 inches tall 

Multi-family residential 

Single Family residential 

Ultra-low flow 


Enough water to cover an acre of land one-foot deep (i.e., 325,851 gallons, or 43,560 cubic feet). 

A screen-like component of a faucet or showerhead that reduces volumetric flow by introducing air into the stream of water. 

As-built plans 
Site plans reflecting the actual constructed conditions of a landscape irrigation system or other facility installation. 

Backflow prevention device 
A safety device used to prevent contamination of the potable water supply from the reverse flow of water from an irrigation system or other customer activity back into the potable distribution system. 

The use of water to clean filters. Water under high-pressure is pumped in reverse through filters, removing trapped sediment and other material. 

Billing cycle 
The regular interval of time when customer’s meters are read and bills are issued, generally every month (monthly) or two months (bi-monthly). 

Billing unit 
The unit of measure used to bill customers, either 100 cubic feet (abbreviated HCF or CCF) or 1000 gallons (kgals). 

Compound meter 
A meter with two measuring chambers, generally a turbine for high flows and a positive displacement for low flows. 

The process of removing salt from brackish water or sea water, producing water suitable for fresh water uses and a concentrated brine. 

Drip irrigation 
The slow, accurate application of water directly to plant root zones with a system of tubes and emitters usually operated under reduced pressure. 

An extended period of below-average precipitation resulting in a reduction of water in available storage that can result in a cutback in water service to customers. 

Something that flows out, such as wastewater, treated or untreated, that flows out of a wastewater treatment plant, sewer, or industrial outfall. 

End use 
A fixture, appliance, or other specific object or activity that uses water. 

ET factor 
A factor used to set a landscape water efficiency goal. Also know as an "adjustment factor". 

Untreated wastewater that has not been contaminated by any toilet discharge, has not been affected by infectious, contaminated, or unhealthy bodily wastes, and that does not present a threat from contamination by unhealthful processing, manufacturing, or operating wastes. Graywater can be used for non-potable applications such as irrigation. Graywater includes wastewater from bathtubs, showers, bathroom washbasins, clothes washing machines, and laundry tubs but does not include wastewater from kitchen sinks or dishwashers. 

Water that has seeped beneath the earth’s surface and is stored in the pores and spaces between alluvial materials (sand, gravel or clay). 

Groundwater recharge 
Percolating or injecting water into a groundwater basin to increase the available groundwater supply. 

Instream uses 
The beneficial uses of water within a river or stream, such as providing habitat for aquatic life, sport fishing, river rafting or scenic beauty. 

Irrigated area 
The portion of a landscape that requires supplemental irrigation, usually expressed in square feet or acres. 

Irrigation controller 
A mechanical or electronic clock that can be programmed to operate remote-control valves to control watering times. 

Irrigation station 
A group of irrigation components, including heads or emitters and pipes, controlled / operated by a remote control valve. 

Landscape water budget (LWB) 
A volume of applied irrigation water expressed as a monthly or yearly amount, based on ETo and the plant material being watered. 

Leak detection 
The procedure of pinpointing the exact location of leaks from water pipes and fittings. 

Master meter 
A single meter that measures utility usage for an entire property, or an entire building, which usually includes common areas. 

Meter (water) 
An instrument for measuring and recording water volume. 

Meter register 
Mechanical device (sometimes used synonymously with the term "Face") that uses a system of gear reductions to integrate the rotation of the moving element of a meter’s measuring chamber into numerical units. 

Mixed use meter 
A water meter that serves more than one type of end use, such as an office building and its surrounding landscape. 

Non-potable water 
Water that does not, or may not, meet drinking water quality standards. 

Peak use (demand) 
The maximum demand occurring in a given period, such as hourly or daily or annually. 

Per capita residential use 
Average daily water use (sales) to residential customers divided by population served. 

Positive displacement meter 
A type of water meter used to measure relatively low flows (such as residential uses). 

Potable water 
Water that meets federal and state water quality standards for water delivered to utility customers. 

Pounds-per-square-inch (psi) 
A unit measure of pressure. In this case, the pressure exerted by water in a distribution system. 

Pressure regulating valve 
A device, often installed downstream of the customer meter, to reduce high pressures to a set amount. Often required where the existing system pressure exceeds 85 psi.

Pressure zone 
A three dimensional zone in the water distribution system where the pressure is allowed to vary only within certain limits, generally dictated by the elevation of the water tank serving the zone. 

Reclaimed water 
Municipal wastewater effluent that is given additional treatment and distributed for reuse in certain applications. Also referred to as recycled water. 

1) Replacement of existing water using fixtures or appliances with new and more efficient ones. 2) Replacement of parts for a fixture or appliance to make the device more efficient. 

Use of treated municipal wastewater effluent for specific, direct, beneficial uses. See reclaimed water. Also used to describe water that is captured on-site and utilized in a new application. 

Reverse osmosis 
A process to remove dissolved solids, usually salts, from water. Salty water is forced through membranes at high pressure, producing fresh water and a highly concentrated brine. 

Riparian rights 
A water right based on the ownership of land bordering a river or waterway. 

Surface flow of water off of a specific area. 

Seasonal demand
Partitioning of demand into baseline use (in the winter) and higher use due to seasonal factors such as irrigation and evaporative cooling. 

Secondary treatment 
The second step in most wastewater treatment systems, which removes most of the oxygen-demanding substances (organics) and light suspended solids. Disinfection is often the final step of secondary treatment. 

Secondary wastewater treatment plant 
A facility that employs secondary wastewater treatment. 

Service area (territory) 
The geographic area(s) served by a utility. 

An irrigated area controlled by a single irrigation valve. 

The practice of using meters to measure master-metered utility consumption by individual users. Also, see partial-capture submetering and total-capture submetering. 

The lowering of ground surface due to extraction of material from subsurface. Can be caused by water or oil extraction from the ground. 

Surface water 
Water that remains on the earth’s surface, in rivers, streams, lakes, or reservoirs. 

Water use efficiency 
A measure of the amount of water used versus the minimum amount required to perform a specific task. 

Water-efficient landscape 
A landscape that minimizes water requirements and consumption through proper design, installation, and management. 

A land area, defined by topography, soil, and drainage characteristics, within which raw waters are contained. They can collect to form a stream or percolate into the ground. 

Landscaping practice based on seven principles: proper planning and design; soil analysis and improvement; practical turf areas; appropriate plant selection; efficient irrigation; mulching; and appropriate maintenance. 

Units of Measurement

acre-feet, = 325,851 gallons or 43,560 cubic feet 

acre-feet per year

Hundred cubic feet = 748 gal. 

Cubic feet = 7.48 gal. 

Gallons, 1 gallon = 0.134 cubic feet 

Gallons per capita per day 

Gallons per day 

Gallons per flush (of a toilet or urinal) 

Gallons per minute 

Gallons per square foot 

One thousand gallons = 134 cubic feet 


Million gallons 

Millions of gallons per day 

Millions of gallons per year 


Pounds per square inch 

Square feet 

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