Protecting your town’s water from residential cross contamination

Posted in: Infrastructure, Water


residential water cross connection contaminationPreventing cross contamination in drinking water

Concerns regarding our drinking water continue to rise. It’s easy to look at the industrial facilities in our communities as potential large-scale hazards to our drinking water — but what about the “do-it-yourself” plumber next door? Potential contaminates to your drinking water are more common than you might imagine. Cross connections are everywhere, and backflow events happen every day. We need to worry about protecting not only our source water, but also the water already in our distribution systems.

In plumbing terminology, a cross connection installation is when drinkable water might pass or contacts other water that is not potable. This type of contact typically due to a backflow event, which is caused when water pressure drops and the flow of water is reversed. Pressure drops are hard to prevent, making backflow events difficult to eradicate. We can help protect our clients by using the proper backflow devices on potential cross connections, and by regularly inspecting water customers at point of use.

Potable water safety campaign

When I approach this problem with a municipal client, my first step is to help educate the residential water customer. Individuals need to understand the necessity of protecting their drinking water, and education is the best way to start the process.  Residential cross connections are more common than nonresidential cross connections, and most backflow events go reported.  Not all backflow events cause health concerns as some may only cause aesthetic issues such as color, taste or odor.

Common residential cross connections that go unprotected are lawn irrigation systems, laundry sinks, hose bibs, claw foot tubs, boiler systems and water softeners.

The city’s website and e-newsletter can be used to explain what cross connections are, as well as simple measures residents can take to protect their water. When we show residents how to protect themselves and their neighbors, we help create a safer community for everyone involved.

Gather information regarding possible water contamination

The next step is to find out how the water is being used. I recommend surveying residential customers. As the water provider its important for municipal leaders to know how the water is being used so they can take measures to protect it.

One of the best ways to gather this information is an in-home survey, where the water supplier enters a resident’s home and inspects the water supply from the point of entry to the point of use. This way, the water provider can identify potential cross connections, take inventory of backflow devices and recommend corrective actions. There are multiple problems with this approach, such as scheduling conflicts with homeowners, homeowner privacy and security concerns, and a lack of experienced staff needed to complete this type of survey.

Fortunately, today’s technology allows us to circumvent the pitfalls of in-home surveys. We can conveniently and efficiently identify potential hazards with a digital survey. At Mead & Hunt, we regularly create online surveys for homeowners to complete themselves. These surveys can be emailed to each homeowner, sent as a link on the water bill or even posted to the city’s Facebook page or website. And the homeowners don’t need to be particularly water-safety savvy—the surveys use pictures to help homeowners identify potential hazards and inventory backflow devices.

The software we use takes the completed surveys and categorizes any potential hazards found within them. It also takes an inventory of all backflow devices for each residence. It then compiles all the data to give a complete picture of all potential drinking water hazards within that community.

Developing a schedule to monitor drinking water quality

This survey is not a “one and done” deal. In fact, if done correctly, it should become a regularly-scheduled survey that the water provider sends out based on the level of hazard and backflow device testing schedule.

For the safety of residents, water providers should have a Cross Connection Plan approved by the proper regulatory agency in their state. This plan should identify the frequency of these surveys, as well as the frequency of the testing of backflow devices. My rule of thumb is to perform a survey on high hazard residential water customers every 2-3 years, and low hazard residents every 10 years. Testable backflow devices should be tested per the manufacture’s guidelines, which typically requires annual testing.

My final bit of advice? Don’t be afraid to ask for help. Clean drinking water is critical to safety of your community.


Casey Rose

About the Author

Casey Rose has worked in the wastewater industry for nearly 20 years with experience working for municipalities and consultant contract operations. Casey is well-known for his ability to build a strong relationships with each client and has a robust background in operations, safety, client communication, construction management and fiscal responsibility.

Read more posts by Casey Rose

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