Water Glossary: Acronyms, Definitions, & Units of Measurement

AC 
Alternating current 

ASCE
American Society of Civil Engineers, www.asce.org 

AMI
Advanced Metering Infrastructure

AMR 
Automatic meter reading equipment 

ANSI 
American National Standards Institute, www.ansi.org 

ARM 
Automated remote metering 

ASME 
American Society of Mechanical Engineers, www.asme.org 

AWC 
Average winter consumption 

AWE 
Alliance for Water Efficiency 

AWR 
Applied water requirement, the gross amount of water that must be applied to a plant or grass to accommodate evapotranspiration (ET) including runoff and water required to overcome system efficiencies 

AWWA 
American Water Works Association, www.awwa.org 

BMP
Best management practice 

CALFED 
A joint effort by state and federal agencies to resolve water supply and quality issues involving the San Francisco Bay and Sacramento-San Joaquin Delta. 

CALWEP
California Water Efficiency Partnership (Formerly CUWCC), https://calwep.org

CC&Rs 
Conditions, covenants, and restrictions 

CEE 
Consortium for Energy Efficiency, www.cee1.org 

CI 
Commercial and Industrial 

CII 
Commercial, industrial, and institutional 

CIMIS 
California Irrigation Management Information System, www.cimis.water.ca.gov/ 

CIS 
Customer information system 

CUSTID 
Customer identification number 

CUWCC
California Urban Water Conservation Council. See CALWEP

DC 
Direct current 

DCU 
Data collection unit (in an AMR system) 

DU
Dwelling Unit 

DU
Distribution uniformity- a measure of irrigation efficiency 

DEIR 
Draft Environmental Impact Report 

EF
Energy factor 

EGLS 
Estimated generalized least-squares 

EIS 
Environmental Impact Statement 

EPA
Environmental Protection Agency (US government), www.epa.gov 

EPAct 
Energy Policy Act, first implemented in Oct. 1992 

ER 
Effective rainfall 

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

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

HD 
High density, refers to MF and other types of units constructed in dense configuration 

HOA 
Homeowners association

HUD
U.S. Department of Housing and Urban Development, www.hud.gov 

IA 
Irrigation Association, www.irrigation.org 

ICI
Industrial, commercial, institutional

IE 
Irrigation Efficiency 

ILI 
Infrastructure Leakage Index 

IRP 
Integrated resources planning 

KL 
Landscape coefficient (includes crop coefficient, and coefficients for shade and slope) 

LF 
Low-flow 

LPM 
Liters Per Minute 

LPH 
Liters Per Hour 

LPF 
Liters Per Flush 

LEED 
Leadership in Energy and Environmental Design (U.S. Green Bldg Council) www.usgbc.org/LEED/ 

LID 
Low-impact development (for storm water quality) 

MaP 
Maximum performance testing (of toilets and other fixtures). This is a trademarked label. 

MEF 
Modified energy factor 

MF 
Multi-family dwelling unit 

MFR 
Multi-family residential 

MIU 
Meter interface unit. Also known as a Telemetry Interface Unit. 

N 
Number. The number of cases from which a summary statistic or analysis is derived. 

NIST 
National Institute of Standards and Technology, www.nist.gov  

NPV
Net present value of a series of payments, costs, or benefits 

P-value 
The probability value of a statistical hypothesis test; the probability of getting a value of the test statistic as extreme or more extreme than that observed by chance alone, if the null hypothesis is true. 

PAC 
Project advisory committee 

POC 
Project oversight committee 

POU 
Point of use 

PUC 
Public utilities commission 

PV 
Present value of a series of payments, costs, or benefits 

OLS 
Ordinary least squares 

R2 
Coefficient of determination 

RBC 
Read, bill, and collect 

REUWS (aka REUS) 
Residential End Uses of Water Study (AWWA 1999, 2016). 

RF 
Radio frequency 

RMSE 
Root mean square error 

RUBS 
Ratio utility billing systems, a calculation method that uses a compensation factor to allocate utility costs among users, most often used in the context of multi-family or commercial billing 

SCS 
Soil Conservation Service now Natural Resources Conservation Service, www.nrcs.usda.gov/ 

SF 
Single-family dwelling unit (detached unless otherwise specified) 

SWAT
Smart Water Application Technology: class of irrigation controllers using soil, weather, or ET-based measurements to control irrigation scheduling 

St. Dev. 
Standard deviation 

SUR 
Seemingly unrelated regression

SWRS 
Subregional water reclamation system 

t-test 
An inferential statistical test for comparing two means. A dependent or paired t-test is used to compare the mean difference score between paired measurements. 

UARL 
Unavoidable annual real losses 

ULF 
Ultra-low flow 

ULFT 
Ultra-low flow toilet. Standard "low consumption toilets". Refers to toilets which consume 1.6 gallons (6 liters) or less of water when flushed. A bit of a misnomer as toilets do not "flow" unless they are broken and are wasting water. 

UNAR 
Unified North American Requirements for toilet fixtures (and other devices) 

WD 
Water district 

WF 
Water factor 

WRF
Water Research Foundation

WW 
Wastewater