Mesa Water is committed to protecting the health of its customers by providing safe, reliable, high-quality water to the communities we serve. Here are just some of the methods we use to validate the safety and cleanliness of our water supply.

Backflow Prevention

Backflow prevention devices protect water supplies from contamination.

Water distribution systems are designed so that water flows from the distribution system to the customer. Though rare, hydraulic conditions in the system can cause the water to deviate from “normal” conditions and flow in the opposite direction. Cross-connections, permanent or temporary, are also possible, and Mesa Water District takes steps and coordinates inspections to ensure that backflow prevention devices are properly installed and comply with the laws protecting the public water supply. Mesa Water works with State, County, and other local agencies to assist customers with procedures for installing and maintaining backflow prevention.

The following Backflow Prevention Device Testers are certified by the Orange County Health Care Agency, Division of Environmental Health. Access the active backflow tester list here.


The Mesa Water supply, like Metropolitan Water District, is treated with chloramines, a combination of chlorine and ammonia. Chloramines are effective in controlling the growth of bacteria and other microorganisms that may cause disease. Chloramines form fewer disinfection byproducts and may have no odor.

People who use kidney dialysis machines may want to take special precautions and consult their physician for the appropriate type of water treatment before consumption. Also, customers who use fish ponds, tanks or aquaria should also make necessary adjustments in water quality treatment, as the disinfectants may be toxic to fish.

Water Main & Hydrant Flushing

As part of Mesa Water's regular preventative maintenance program to remove normal sediment buildup from the pipes that deliver water to its customers, Mesa Water performs unidirectional flushing of the water mains and fire hydrants. This improves the quality and appearance of the water.

Customers will be notified when flushing is scheduled to begin in their area. During flushing you may notice some discoloration or sediment in your tap water, affecting only its appearance. The water is safe and will clear up in a few minutes when you run cold water through the faucet of your bathtub or other unscreened tap such as a backyard garden hose.

For more information on Mesa Water's flushing program call the Water Quality Department at 949.574.1031.