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Water Loss Control Resources

Implementing a formal water loss control program is important to managing a water system and ensuring adequate supply. Leak detection and repair are the traditional activities associated with water loss control, but a water loss control program takes a more comprehensive and closer look at losses and the costs and benefits of controlling them.

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Water Audits

The foundation of a community’s water loss control program is a water audit. Water audits provide water suppliers with a means of accounting for water, identifying and tracking water lost to distribution and service leaks or storage tank leaks and overflow, and identifying revenue lost through meter inaccuracies, data handling errors, and theft. Controlling these losses not only can make better use of water resources, but can also increase revenue. 

Why Perform a Water Audit?

Why perform a water audit?

Water audits are important for:

  • Evaluating quality and efficiency of operations
  • Understanding the nature of water losses and managing their magnitude
  • Reducing the amount of non-revenue water and identifying cost savings
  • Maintaining confidence with customers and decision makers
  • Setting capital priorities

What Tools are Needed for a Water Audit?

What tools are needed for a Water audit?


  • Water audit software- this is free and can be obtained online. The American Water Works Association (AWWA) provides a free Microsoft Excel spreadsheet based audit software on their website. See links below.  The software is based on the AWWA Manual of Water Supply Practice M36 “Water Audits and Loss Control Programs.” This “M36 method” has become the industry standard is and recommended by Massachusetts Department of Environmental Protection. (MassDEP)
  • Microsoft Excel 2010 or later is needed run the AWWA M36 spreadsheet
  • American Water Works Association (AWWA) Manual “Water Audits and Loss Control Programs M36”, 4th Edition or most recent edition is strongly recommended as a reference material and is available through the AWWA online store
  • Free guidance materials are also available through MassDEP and the Environmental Protection Agency.  See the links below.

What Data Will you Need?

What data will you need?


Accurate data are needed for the water audit period selected including:

  • Water Supplied: Volumetric data of water pumped from sources and distributed through the supply system and any imported or exported water
  • Authorized Consumption: Billed metered, unbilled metered, billed unmetered, and unbilled unmetered (for example from flushing  street cleaning, and firefighting)
  • Potential errors in customer metering (accuracy of customer meters) and potential errors in production meters
  • Estimates of losses within the supply system
  • Basic infrastructure and operational information about the distribution system- information about service connections, lengths of mains, and average distribution system pressures
  • Financial information including water rates and production costs

Who Should be Involved?

Who should be involved?


  • Key personnel involved with water treatment, distribution, and meter installation, reading, and billing
  • Consider assembling the key personnel into a team and have a kick-off meeting to discuss the purpose of the audit and ask questions on how data are collected.
  • It is recommended to have a third party water audit validator or “another set of eyes” assist in validating the audit and providing objective analysis and feedback.
  • After entering the data in the M36 software, scrutinize the validity of the data and follow-up with key personnel to fine-tune the audit. 

What Information Will a Water Audit Provide?

what-information will a water audit provide


  • The M36 Water Audit Software provides a “water balance.”  A water balance is a summary of the audit water data.  The losses are categorized as “apparent losses,” losses from water consumption that is not properly measured or billed and “real losses,” actual leakage. The water balance also categorizes the losses into revenue and non-revenue water.  It is an overall picture of the water audit data.
  • Data Validity Score- This is a measure of how accurate and reliable the data are and an assessment of best practices used by the supplier.  In addition, the Water Audit Software includes a grading matrix with guidance for improving the quality of data.
  • Performance Indicators- The Water Audit Software includes some Performance Indicators to help suppliers set benchmarks for themselves.

Things to Keep in Mind

Things to keep in mind


  • Be skeptical: are the data representative, complete, accurate, and reliable?
  • A “Level 1 Audit” is recommended by AWWA as a starting point as a supplier starts to do annual audits.  A Level 1 Audit provides a way of assessing the accuracy and validity of the data used
  • Be pragmatic: given available resources, focus on your goals and what actions can make the biggest difference in assembling reliable data
  • Set aside enough time to acquire the data and perform the evaluations. Compiling, validating, and analyzing information will be a significant effort, but is essential to meaningful results. It can be difficult to obtain the proper data and schedule meetings with the appropriate personnel, but in the end it is worth it
  • Document how you collect the data; this will streamline future audits and help identify areas of improvement
  • An annual water audit in addition to defining program goals and assessment measures
  • Record keeping, including tracking losses, leaks, and repair information
  • A closer look at pressure management; optimizing pressure to minimize losses and surge impacts, might not only minimize leaks but also extend the life of the water infrastructure
  • System assessment and maintenance and standards for installation and repairs
Old Water Mains

Water audits aren’t a “check the box” one-time activity.  Water audits are a management tool and they inform decision making so it is important to take the time to get it right. Several years of data refinement and comparison may be required before you are confident that your data are reliable enough to move on to other more involved water loss control activities as part of a water loss control program.  Before time and money are spent on these activities, it is important to determine if they are the most appropriate course of action.

Putting it all Together: Water Loss Control Program

Putting it all together- Water Loss Control Program


Evaluating water loss control activities undertaken for their effectiveness is integral to successful water loss control. Evaluating data, tracking progress, comparing results to industry benchmarks and performance indicators, and identifying areas for improvement are the last steps in water loss control and are important for refining water loss control activities. A formal water loss control program consisting of all the above practices together with goals, assessment measures, and assigned responsibilities will help suppliers: reduce unnecessary water withdrawals, environmental impacts from those withdrawals, and pumping and treatment costs; bolster revenue collection by addressing metering inaccuracies and unauthorized water use; and target maintenance efforts and infrastructure investments to minimize system disruptions and improve system integrity.

Communities should develop and implement a water loss control program. Guidance on water loss control programs can be found in EPA’s “Control and Mitigation of Drinking Water Losses in Distribution System” as well as AWWA’s M36. Communities may already be performing many aspects of a water loss control program. Items to include in a water loss control program are:

  • An annual water audit to better focus efforts on reducing real and apparent losses.
  • Program goals and assessment measures.
  • Record keeping, including tracking losses, leaks, and repairs.
  • Leakage management program.  Leakage management includes leak detection surveys and repair and depending on the system may include zone flow analysis, district metered areas, and pressure management.
  • System assessment and maintenance. To help eliminate and prevent leaks and water loss, water suppliers should perform assessments of their systems on a regular basis to determine where capital improvements are appropriate and incorporate the recommendations into a long-term capital improvement program. Specifically, aged and undersized or structurally deteriorated pipe should be replaced, and structurally sound pipe should be cleaned and lined to ensure long-term structural integrity.
  • Standards for installation, repairs, rehabilitation, and replacement of pipe. Poorly executed pipe installation and workmanship can contribute to unnecessary leakage, especially work done on service connections. All pipe work, repairs, and connections should be designed properly, executed properly, and inspected.

Lessons Learned

Lessons Learned SubHeader


MassDEP has been distributing grants for AWWA M36 water audits for communities since 2013. Those audits have identified some areas that tend to be problematic for systems. 

  1. Volume from own sources is important- the accuracy of master meters, both the calibration of electronics and flow components
  2. Customer metering inaccuracies- the QA/QC, reading versus billing databases lead to billing inaccuracies; there are also aging/inaccurate meter populations
  3. Systematic data handling errors- the data collection and unbilled unmetered usage

Appendix A in the M36 audit instructions found on MassDEP’s website includes a guide for collection of data for the audit. 

Case study cover page

Data should be collected before starting the water audit. Knowing the source and having confidence in the data is integral to completing the M36 water audit.

Links to American Water Works Association M36 Water Audit Training Document prepared for the MassDEP by Weston & Sampson Engineers, Inc.

Funding Resources to Tap

Funding Resources to Tap

There are four state grants available for funding water conservation related municipal projects:

  1. MassDEP Water Management Act grants provide public water systems funding for planning assistance, conservation/demand management, and withdrawal impact mitigation projects. Specific applications include watershed planning projects to improve ecological conditions; conservation projects aimed to reduce demand, including rate studies or drought resiliency planning and wastewater management projects.
  2. MassDEP M36 Grant: M36 grant recipients receive a free AWWA "Top Down" Audit from consulting firm hired through the public procurement process.  For certain PWS that meet the outlined data criteria, a "Bottom-Up Component Analysis" may also be done as part of the Audit. 
  3. State Revolving funds. Details on the MassDEP grants and State Revolving funds can be found here
  4. Municipal Vulnerability Program (MVP): Check here for Municipal Vulnerability Program Action Grant details. Water conservation projects are eligible under the Action Grant program. Action Grants are available to communities that have been through the planning process and have been designated as an MVP community.

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