Water Loss and Conservation for Small Utilities

Water loss is an unavoidable part of distribution systems, yet too much can stress the supply and efficiency of your utility. The average water loss for systems is estimated at 16 percent, up to 75 percent of which is recoverable. This water may be disappearing due to faulty or aging infrastructure via pipe breaks and leaks, storage overflows, and house connection leaks. It’s also possible the water loss is only apparent, not real, due to errors like unauthorized consumption or inaccurate meters.

Identify your water loss

Your utility can calculate water loss as the difference between system input (the volume of water your utility delivers), and consumption (the volume of water that can be accounted for by legitimate consumption, whether metered or not.) The EPA outlines the following calculations in their overview of water audits and water loss control:

1. Determine the amount of water added to the system, typically for a one year period,
2. Determine authorized consumption (billed + unbilled), and
3. Calculate water losses (water losses = system input – authorized consumption)
   1. Estimate apparent losses (unauthorized consumption  + customer meter inaccuracies + billing errors and adjustments)
   2. Calculate real losses (real losses = water losses – apparent losses)  

For a quick estimate, you can also use the Monthly Water Loss Calculator from the Missouri Rural Water Association. If you aren’t sure of the right numbers to plug into these calculations, your system may need a water audit. Maryland’s Water Supply Program offers guidance on preparing for water audits and linking them to a water loss reduction plan.

Identify your action items

Once your water loss calculations have determined whether you should take conservation actions, you’ll have a host of options to choose from. One of the most comprehensive overviews in our WaterOperator.org library comes from the Florida Rural Water Association, which not only lists options available but grades the water savings, cost effectiveness, and ease of implantation for each. In general, most of your options will fall under:

• Meter installation, testing and replacement
• Leak detection and management
• Pipe repair and replacement
• Correcting water theft and meter tampering
• Setting conservation rates, if appropriate

If your utility is functioning well, or if you’re unable to make changes but facing a water shortage, you can also work directly with customers to change their usage habits. We’ve found few compilations of home water conservation tips more extensive than this 100+ item list compiled by the Water Use It Wisely.

Evaluate performance

Finally, your utility will want to set benchmarks for the interventions and check back on your calculations periodically to see how the system improves. To find more resources on how to identify and correct water loss, including those specific to your state, be sure to check our document database at wateroperator.org/library.