Frequently Asked Questions for Water Use Survey

Water Use Survey

Water Use Estimates (State, Region, and County)

Water Use Estimates (City)

Answers to Frequently Asked Questions

Is the Water Use Survey required and when is it due?

  • Yes, the return of a completed survey is required under Texas Water Code 16.012 and Texas Administrative Code 358.5 for any entity that has received the survey. The completed survey is due 60 days after receipt. Letters notifying recipients are mailed in late December and the online survey is available by the first business day in January, so the due date is set as the first business day in March.

Back to top

What are the criteria for determining who receives a survey?

  • There are two types of surveys available each year: Municipal and Industrial. Annually, the TWDB surveys approximately 7,000 water systems and industrial facilities in the state. This number represents roughly 4,500 municipal and 2,500 industrial water use surveys.

    Municipal Water Use Surveys are required of public water systems that are a community type with the potential to serve at least 15 residential connections on a year-round basis, or serves at least 25 residents, as indicated by 30 TAC §290.38(14). Water systems and commercial/institutional-type facilities that do not meet the above criteria (often wholesale-only systems), but pump groundwater, may also be surveyed, particularly if they pump GW.

    Industrial Water Use Surveys are required by industrial water users are required by industrial water users that:
    • Annually use more than 10 million gallons of water, or
  • Use a significant volume of water for the industrial sector or more for the particular area of the state. The second criteria noted is most often applied to small facilities in rural areas that make up a significant portion of a county's industrial water use. Because the Water Use Survey Program has a long history, some water systems or industrial facilities may have been missed or not surveyed in the past. However, the Board Staff attempts to include all water systems or industrial facilities that meet the above criteria.

Back to top

If a system/facility already reports water withdrawals to the other governmental entities, such as the Texas Commission of Environmental Quality, local groundwater conservation districts, subsidence districts or water wholesalers, then why is it necessary to fill out the annual Water Use Survey?

  • The Water Use Survey is intended to collect a comprehensive view of groundwater and surface water use across the state for water supply planning. While the volumes reported to other entities may be identical to what is reported in the water use survey, the local reporting provides only a partial picture of water use geographically and by source. Resources do not currently exist to coordinate the collection of water data between all agencies, districts and authorities involved

Is this the same as the TWDB's required Water Conservation Plan Annual Report or the Water Loss Audit?

  • No, the Water Use Survey is separate from the Water Conservation Plan Annual Reports and the Water Loss Audit, although all are administered by the TWDB and a number of questions are the same or are very similar. Though some water systems may be required to fill out the Survey, Report and Audit in a given year, the criteria for all three instruments are different, so some systems may fill out only one, two or all three of the forms. A number of questions pertaining to categorical water use are required to be collected in the Survey and the Report: In these cases, the survey attempts to specify which questions are identical to those in the Conservation Report.

Back to top

Are all survey questions required or are some optional?

  • The survey requires that all questions be answered to the best of the system's or facility's capabilities. If questions do not apply, or are unknown due to a system's billing limitations, please make note of this in the comment section.

Back to top

What do we need to do if our survey is returned as incomplete?

  • Surveys are returned if questions are left blank with no notation indicating that the question does not apply or cannot be answered. Until the survey is returned with the missing information, the survey is not considered returned for the purposes of TWDB financial assistance and water-right application requirements. Please contact Survey staff if there are questions regarding missing information.

Back to top

How do I determine which aquifer my water well pulls from?

  • Please click on our board Map of Major Aquifers. If further assistance is needed, please contact Water Use Survey Hotline phone number at (512) 463-7952.

Back to top

Why is my water use intake total in the pdf form not calculating correctly?

  • Do not enter or paste a comma separator or a decimal point for the monthly intakes on the survey form. Enter the intakes only as whole numbers without commas. The total annual volume will be automatically calculated with comma separators.

Back to top

How much is an Acre-Foot?

  • An acre foot equals 325,851 gallons which is an amount of water sufficient to cover one acre with one foot of water.

Back to top

Where does the TWDB get this data?

  • Water use estimates for municipal, manufacturing, and steam-electric power categories come from an annual survey of public water suppliers and major manufacturing and power entities. Response to this survey is mandatory (Section 16.012(m) of the Texas Water Code, as amended by the 78th Texas Legislature in 2003).
  • Mining water-use estimates are based on the annual water-use survey and an estimate of the water used in secondary processes for oil and gas recovery.
  • Livestock water-use estimates are derived from annual livestock population estimates produced by the Texas Agricultural Statistics Service. Estimated water use per animal unit is based on research conducted by the Texas Agricultural Experiment Station.
  • Estimates of irrigation water use (up through 2002) were based upon five-year irrigation surveys conducted in coordination with the U.S. Department of Agriculture-Natural Resources Conservation Service. Irrigation water use estimates (2003 and later) are developed through the use of various datasets including, but not limited to, available weather data, irrigated acres from the U.S. Department of Agriculture-Farm Service Agency, surface water diversions from the Texas Commission on Environmental Quality, and local revisions from groundwater conservation districts and other local political subdivisions. More information on this process may be found on the Irrigation Water Use Estimates webpage.

Back to top

How are the water use and pumpage volumes estimated?

The TWDB estimates water use at the city level for cities which have population of 500 or greater and for county seats. Gross water use is collected for municipal water suppliers, subtract sales to other water suppliers, and attribute some portion of the utility's net use to particular cities. County estimates are the sum of net water use from municipal utilities and rural users in each county.

Water use for manufacturing is the summation of water use for manufacturing firms reporting to the TWDB. Water use for power is a combination of reports and calculations of consumed water based on individual water supply power plant configurations. Mining water use is a combination of reported water use by firm and additional estimates based on prior years' research. Irrigation is provided annually by the TWDB Conservation Division and is based on crops, acreage, climatic conditions, and observations by local agricultural representatives, and data provided by irrigation and groundwater districts. Livestock data is calculated annually from Texas Department of Agriculture livestock population reports by animal class compiled by the TWDB Conservation Division.

The Water Use Survey Team has created ground water pumpage estimates by aquifer since 1985, with the cooperation of TWDB staff geologists. Each municipal and industrial entity surveyed has an assigned major aquifer, so reports of ground water pumpage by municipal and industrial users can be summed. Pumpage estimated for residual county-other municipal water use, residual mining water use, irrigation, and livestock has been distributed to the thirty major aquifers according to research and professional opinion of TWDB geologists.

Back to top

What types of water use are included?

  • Municipal water use includes: City-owned, districts, water supply corporations, or private utilities supplying residential, commercial (non-goods-producing businesses), and institutional (schools, governmental operations).
  • Manufacturing is process water use reported by large manufacturing plants.
  • Steam-Electric Power is consumptive use of water by large power generation plants that sell power on the open market, generally not cogeneration plants that generate power for manufacturing or mining processes.
  • Mining water use: Include water used in the mining of oil, gas, coal, sand, gravel, and other materials.
  • Livestock water use.
  • Irrigated agriculture water use.

Back to top

How is the Gallons per Capita Daily (GPCD) calculated?

  • Net Use allocated to the Water User Group (WUG) in gallons, divided by a Population Estimate, divided by 365 days. Net Use is defined as the volume of water taken into the system or systems of a city, minus water sales to other water systems and large industrial facilities. For specific information regarding the calculation of GPCD, please contact the Water Use Survey Team by telephone at (512) 463-7952.

Back to top

Why are the Gallons per Capita Daily (GPCD) not shown for my local utility?

  • Estimates of Gallons per Capita Daily (GPCD) have been made annually since 1980, intended for the express purpose of projecting the future water needs of each city, and are intended to reflect water uses that can be expected to grow along with population. Historically, available methodologies for projecting future population have been centered on counties and cities. Thus, water use estimates are adjusted to reflect the population of entire cities, and are not published on an annual basis for specific utilities.
  • If you are interested in data related to a specific non-city utility, please contact the Water Use Survey Team by telephone at (512)463-7952 or by email to Water Use Survey Team.

Back to top

Why is the TWDB's per-person water use figure (gallons per capita daily or GPCD) different from the one that my local utility has published?

  • It is not unusual for GPCD (Gallons Per Capita Daily) figures to vary due to differing methods of calculation. In the calculation of a city or utility's water use (and ultimately, the GPCD) for regional water planning, the TWDB:
  • Includes the water use of residential, commercial and institutional users, as well as process-related water loss and any system water loss.
  • Does not include water sales to large manufacturing, mining or steam-electric power plants.
  • Does not include a city's water sales to retail customers who live outside of the city limits.
  • Includes the water use of commercial and institutional entities, and residential customers, who are within the city limits but are supplied water from another source, including a private groundwater well, another water utility or a surface water right.
  • Because each water utility plans for the total water demand expected by all of its customers; a water utility, when calculating its per-capita use (GPCD) may include all of its customers (residential, manufacturing, and wholesale), regardless of whether they are within the city limits or not.
  • Finally, the per-person water use is calculated not only with the amount of water used, but also the population. The TWDB's per-person water use calculation utilizes the annual population estimates of cities produced by the Texas State Data Center: Office of the State Demographer. If a water utility calculates the per-person use with a different population estimate, the per-person usage will differ from TWDB's.

Back to top

What is Residential GPCD and how is it different?

  • For the first time in the 2007 use estimates, an estimate of residential water use per capita is included for some of Texas's cities. Residential water use is intended to reflect the water billed to single and multi-family residences, and includes both indoor and outdoor water uses. The remainder, non-residential water use, reflects the water used for all other purposes, primarily commercial (non-industrial) businesses and government institutions, and is a function of the size of the city's workforce and the composition of its businesses, as well as the size of the resident population.

Back to top

If a city is listed with a high GPCD, does that mean that they use too much water?

  • Cities with high per capita water use estimates are sometimes portrayed as being extravagant in their water consumption when compared to cities with low per capita use figures. This is not always true, as a number of factors can legitimately affect estimated per capita use.
  • TWDB estimates are for total municipal water use, defined by the TWDB as water produced by utilities for use not only in homes, but also in most non-goods producing business establishments - retail, lodging, eating and drinking places, and various types of services: professional, legal, medical, financial, educational, in addition to government, and specialties such as regional air transportation centers and professional and college sports venues. All other things being equal, larger cities with a greater concentration of employment in such services and which provide such services to more than a local demand base will legitimately have a higher water use per permanent resident, without indicating that those residents are wasteful in their personal use of water. In contrast, areas with less commercial activity and institutional water users may have much lower figures.
  • Other factors that affect per capita use may include:
    • Variations in regional climates,
    • Population and building density,
    • Regional economic conditions,
    • Quality of water supplies in a given region,
    • Extent and effectiveness of local water conservation programs, and
    • Rates of unaccounted for water in a given distribution system (e.g. leaks from aging distribution infrastructure).
  • In summary, the TWDB recognizes that there are legitimate reasons for differences, and emphasizes that per capita estimates are not intended for making direct comparisons between cities.

Back to top