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Utilities - Cross-Connection & Backflow Prevention

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1. What is a cross-connection?

Common Cross-Connections

Have you ever connected a garden sprayer to the end of a hose to fertilize your vegetables or flowers? Have you ever stuck the end of a garden hose into your car’s radiator or connected it to the heater hoses to flush the radiator? Or, have you ever placed the hose under the water’s surface in a swimming pool and left it on?

Many of us do. However, doing any of these poses a risk of contaminating your home’s drinking water with chemicals that can cause serious health concerns if swallowed.

Cross-Connection Definition

A cross-connection is:

• Any existing or possible interconnection between a drinking water system and any other system that contains a substance of unknown or uncertain quality.
• The link that can bring two systems together.

The most common cross-connection is an outside hose faucet, typically called a “hose bib” or “sillcock.” Use these plumbing fixtures for connecting hoses that you use for various purposes such as watering your gardens, flowers and lawns.

2. What is cross-connection control and why is it important?

Cross-connection control is the methods, practices and procedures used to prevent contamination or pollution of drinking water from backflow through cross connections.

It ensures that your drinking water remains safe from bacteria, chemicals and other substances that may enter the water from unknown or improperly maintained sources because of abnormal pressure changes.

3. What is a cross-connection control program?

A cross-connection control program is a written plan that:

• Detects, monitors and manages cross-connections.
• Implements the procedures and practices necessary to ensure safe drinking water to comply with government rules and regulations.

4. What is backflow and how is it prevented?

Backflow is the reverse flow of water or other substances in pipes, typically caused by unusual and irregular changes in pressure.

Prevent backflow by avoiding the reverse flow of an unwanted substance into the drinking water with special plumbing methods, devices and practices. Prevent backflow by using a physical means or mechanical device designed and built specifically to prevent backflow.

5. What is back-siphonage?

Back-siphonage is the backward flow of water or other substances from one system to another because of a decrease in pressure. The pressure decrease causes the water or substance to draw or siphon backward to the point of lowest pressure, such as at a suddenly-opened valve or hydrant, or at a break in a pipe or a water main.

6. What is backpressure?

Backpressure is the backward flow of water or other substances from one system to another because of an increase in pressure. The pressure increase causes the water or substance to push backward suddenly or over time by a pump, an increase in temperature or because of changes in height (pressure increases as water rises).

7. What is an “approved” backflow prevention method, assembly or device?

Approved backflow prevention methods, assemblies and devices are a physical means or mechanical device that a nationally recognized laboratory, organization or institute tested and approved. These organizations include:

• Factory Mutual
• The Foundation for Cross-Connection Control and Hydraulic Research
• The American Society of Sanitary Engineering
• Underwriters Laboratory

8. What is contamination?

Contamination is the introduction or presence of any foreign substance in a drinking-water system that could or does make the water hazardous to human health.

9. What is pollution?

Pollution is the introduction or presence of any foreign substance in a drinking-water system that could or does change the taste, odor or color of the water and weakens its usefulness but is not hazardous to human health.

10. What is potable water?

Potable water is water that is fit for drinking, cooking and household uses.

11. What are examples of cross-connections around my home or business?

The most common cross connection is an outside hose faucet, typically called a “hose bib” or “sillcock.” Use these plumbing fixtures for connecting hoses that you use for various purposes such as watering your gardens, flowers and lawns.

12. Where in my home or business are backflow prevention methods, assemblies or devices typically found or required?

If you have a toilet with a tank on the back in your home or business, it contains a valve to fill the tank every time you flush. The fill valve, or “ballcock,” is equipped with an approved backflow prevention device that prevents any water in the tank from being siphoned back into the pipes of your house (anti-siphon).

Plumbing Codes

Plumbing codes require all water outlets to be equipped with a backflow prevention method or device to prevent contamination or pollution of the drinking water. Therefore, all sinks have a space between the end of the faucet and the flood level of the sink, called an air gap. Some sinks typically found in commercial businesses, such as a mop sink, are equipped with a backflow prevention device called an atmospheric vacuum breaker installed on the faucet.

Learn More

Visit the Backflow Prevention Assemblies page to learn more.

13. Does my underground lawn sprinkler system require a backflow preventer?

Yes. All underground lawn and garden irrigation systems are required to have backflow prevention assemblies installed and routinely maintained. State and local regulations and codes require such assemblies to be tested at the time they are installed and yearly thereafter, as well as any time they are repaired, relocated, or replaced.

• Residential Irrigation Systems Backflow Prevention Guide (PDF)
• Commercial and Industrial Applications Backflow Prevention Guide (PDF)

14. What test is required and how is it conducted?

A performance test is done to check if the assembly continues to operate as designed and continues to protect against backflow. A specialized test instrument equipped with a large pressure gauge is connected to the backflow prevention assembly with three separate high-pressure hoses that are attached in various techniques to measure the differences in pressure under certain conditions.

15. Who performs the test?

The test must be performed by someone who holds a current certification as a “backflow prevention device worker” issued by the Virginia Department of Professional and Occupational Regulation. The certification ensures you that the tester is specially trained, experienced, and has successfully completed an examination that tests his or her competency in the subject of cross connection control and backflow prevention.

16. Is there anything else required with the test?

Yes. At the time the test is conducted by the certified tester, he or she will complete a backflow prevention assembly test report form, provide you with a copy, and either you or he must send Chesterfield County a copy of the form for the county’s records.

17. Where do I get the backflow prevention assembly test report form, and how and where do I send it?

Mail the Report

Complete the Backflow Prevention Test Report (PDF) and mail to:

Cross Connection Control Coordinator
Chesterfield County Department of Utilities
P.O. Box 608
Chesterfield, VA 23832-0009

Fax the Report

Or, you can fax the report to 804-751-4437.

18. Where do I find a certified backflow prevention device worker?

Check advertisements in the yellow pages of your local telephone book listed under “Plumbing Contractors.” You can also search the internet.

19. How much does the test cost, and who is responsible for payment?

There is no control over the cost of the test. Testers and businesses set their own prices, which are typically controlled by the current market. The owner (property owner, building owner, tenant or homeowner) is responsible for maintenance of the backflow prevention assembly at his or her own expense.

20. Where can I find more information about cross-connection control and backflow prevention?

The Environmental Protection Agency Cross-Control Manual provides more information on:

• Additional examples of assemblies and devices.
• The types of problems that can and have been caused by cross-connections and backflow.
• The principles of water pressure and backflow.