Backflow Prevention Information


Protecting Your Water Against Contamination

Congress established the Safe Drinking Water Act (SDWA) in 1974 to protect human health from contaminants in drinking water and to prevent contamination of existing groundwater supplies. This act and its amendments (1986 and 1996) require many actions to protect drinking water and its sources. One of these actions is the installation and maintenance of an approved backflow prevention assembly at the water service connection whenever a potential hazard is determined to exist in the customer’s system. Without proper protection devices, cross connections can occur.

What is a cross connection?

A connection between your drinking water and another source of water that combines the two when a backflow condition occurs. When this occurs, your drinking water can become contaminated.

OK. So? What is backflow?

Backflow is when the water in your pipes (the pipes after the water meter) goes backward (the opposite direction from its normal flow). There are two situations that can cause the water to go backward (backflow):

  • Backpressure – the pressure in your pipes is greater than the pressure coming in.

  • Backsiphonage – a negative pressure in one of the pipes.

To protect the water system, two kinds of backflow prevention assemblies (devices that prevent the backflow of water) are required for all business customers that present a potential hazard to the water system:

  • External – to protect the water from cross connection with the water on the customer’s premises

  • Internal – to protect the customer from potentially hazardous cross connections in his own system.

What is considered a potential hazard?

ANY possibility of pollutants, contaminants, and system or plumbing hazards. For example: fire protection systems, irrigation systems, gasoline refineries and stations, restaurants, hospitals, and manufacturers. Just to name a few.

To keep your drinking water safe, the City of Clemson Utilities Department checks the plans of each new business for compliance with cross connection/backflow requirements. We take pride in the water we provide and will continue to protect it and our citizens.

Now that you have some background, you may ask…What’s the big deal? Well, the big deal is that backflows due to cross connections can cause sickness and death. Even in your own home, you can unwittingly create a cross connection:

  • Putting the garden hose in a swimming pool to fill it.

  • Putting the garden hose in a pet’s water bucket to fill it, or the fish tank.

  • Putting the garden hose down the drain to flush out debris when it’s backed up.

  • Connecting your garden hose to a plant fertilizer or bug spray unit.

Over half of the nation’s cross connection problems involve unprotected garden hoses.

The City of Clemson Utilities Department protects the water entering your system. However, it is your responsibility to protect the water on your property or in your home. It’s important to note that homeowner irrigation accounts require you to install a backflow prevention device on underground systems and have it tested initially by an approved tester before being placed into service and then every three years after that. A certified plumber or contractor can install a backflow preventer for you. The cost will depend on the type of device required and the installation labor. Testing fees vary, so it’s a good idea to call around for pricing to Certified Testers please follow this link to the SC Department of Health and Environmental Control website for a list of certified testers:

Commercial Accounts generally require the business to have backflow prevention. All fire lines are required to have an approved backflow prevention device. Please contact Tom Luke the Utilities Department if you have questions.

For more information on how to protect the water on your property, please call the City of Clemson Utilities Department Backflow Prevention at (864) 653-2046.