Water Loss Audit
Presentations available from the August 22, 2013 Water Loss Symposium.
Who needs to submit?
Any retail water supplier that has an active financial obligation with the Texas Water Development Board is required to submit a water loss audit annually. Additionally, retail water suppliers with more than 3,300 connections are now required to submit an audit annually. The annual water loss audits for the year 2013 are due May 1, 2014.
In addition, all retail public water suppliers are required to submit a water loss audit once every five years. The next scheduled audit for this requirement is for the year 2015 and will be due by May 1, 2016.
Additionally we encourage all retail public water suppliers to complete an audit annually to assist them in tracking water loss to help better identify issues that may need addressing.
Traditionally, the water utility industry has used percentages to determine water loss, but in order to more efficiently manage your utility you should be able to answer several questions:
- Where did we lose the water?
- How much water was lost, expressed as a volume?
- How much did the loss cost the utility?
- Why did we lose the water?
The Texas Water Development Board utilizes a methodology derived from the American Water Works Association (AWWA) and the International Water Association (IWA). This new standard uses terminology such as authorized consumption, real loss, apparent loss, and non-revenue water.
Authorized consumption is water the utility gave someone permission or authorization to use. Whether it was billed or not, it is still authorized consumption.
We now use the terms Real Loss (water lost through distribution system leakage and excessive pressure), and Apparent Loss (includes water that was not read accurately by a meter, unauthorized consumption, including water taken by theft, data analysis errors and data used for billing). Since real loss is water lost while in the distribution system, a production cost is associated with it. The retail rate is associated with the cost of apparent loss because it had the opportunity to be metered.
Non-revenue water (NRW) is simply water that the utility does not receive compensation for. For clarification purposes NRW consists of the unbilled categories of authorized consumption and both apparent and real loss.
The Water Audit Worksheet is a "top down" audit and is referred to as a "desktop" exercise using existing estimations and records. If the utility desires to become more efficient, the next step in this process is the "bottom up" audit, which involves a detailed investigation into actual policies and practices of the utility. It should be phased in only after the utility staff has a thorough understanding of a "top down" audit and the IWA methodology, terms, and procedures.
For further explanation of this methodology and for detail definitions please review the Water Loss Manual.
The TWDB now provides a secure website to ensure the security of the data provided by water utilities all over Texas. To access the Water Loss Audit Worksheet online you must first register by creating a username and password. The New User link will direct you to that page. Once you have created a username and password, you may use the Registered User link to request access to a particular utility. Once access is approved by TWDB staff you will receive a confirmation by email granting access.
Water Audit Worksheet Resources
For further information or questions, please contact conservation staff.