Bureau of Operations - Drinking Water
Cross-Connection and Backflow Prevention
Frequently Asked Questions:

What is backflow, and why is it dangerous?
What is a backflow prevention device?
Who is required to have a backflow prevention device?
Where should the backflow prevention device be located?
When do I have to have the backflow prevention device installed?
What is a cross connection?
When did installation of the devices become a requirement?

What is backflow, and why is it dangerous?
Water systems are designed to move water in one direction. However, a drop in pressure or a break in a water line can send water flowing in the opposite direction – and draw contaminants such as fertilizers and other chemicals into the drinking water system. This reversal of flow is called backflow, or back-siphoning.

Backflow is dangerous because non-drinkable water, chemicals, fertilizers, etc. In a municipality’s drinking water system can contaminate the water supply and may cause sickness or death.

What is a backflow prevention device?
A backflow prevention device, or assembly, is essentially a pair of check valves placed on a customer service line. The device is configured to shut when there is reverse flow in the water line, thereby keeping contaminants out of the water system.

Who is required to have a backflow prevention device?
All commercial water customers and some residential customers, such as people with irrigation systems and those with certain home-based businesses.

Where should the backflow prevention device be located?
On the customer’s property near the meter box, or immediately inside the building being serviced; but in all cases, before the first branch line leading off the service line.

When do I have to have the backflow prevention device installed?
If you are required to install a backflow prevention device, the sooner the better. The City of Atlanta expects all affected property owners to have backflow prevention devices installed and tested before your business opens. If your business existed prior to your first inspection, get the devices installed as soon as possible.

What is a cross connection?
Any actual or potential connection between the public water supply and a non-desirable source of contamination or pollution.

When did installation of the devices become a requirement?
The Federal Government passed the Safe Water Drinking Act in 1973, and Georgia adopted these federal standards in the same year. In 1977, Georgia passed the Rules for Safe Drinking Water which states”

“A supplier of water or any person having possession or control of a public water system has the responsibility to prevent water from unapproved sources or any contamination from entering the public water system.”

The Georgia Department of Natural Resources Environmental Protection Division amended this rule in 1983 and mandated that all public water systems develop Cross-Connection and/or Backflow Prevention Programs.