Backflow Prevention

Information about Cross Connection and Backflow Prevention

What is a cross connection?

• A cross connection is any temporary or permanent connection between the public water system and any source or system containing non-potable water or other substances.

What is backflow?

• Backflow is the undesirable reversal of flow of non-potable water or other substances through a cross connection and into the piping of a public water or a consumer's potable water system.
• There are two types of backflow: backpressure backflow and backsiphonage backflow.

What can cause backflow?

• Backflow can be caused by a sudden drop in the water pressure in a public watermain, which can create a sub-atmospheric condition.
• For example, if a drop in pressure occurs while a garden hose is in a bucket of dirty water, that water could backflow into the public water system, potentially contaminating the water for other users. A drop in pressure could be caused by a variety of things, including a watermain break or a loss of power at a pump station.

Backflow Prevention

When water is accidentally mixed with hazardous chemicals, it can be extremely dangerous. When any hose is connected to a harmful substance while pressure in a watermain drops, the water and the contaminants could be sucked back into your pipes and water drinking supply. Water pressure drops are not uncommon.

Watch for: Chemicals used as weed killer, insect repellant or lawn fertilizers, cleaners used on your kitchen sink, and even bacteria from your wading pool or waterbed.

To prevent contamination, the following should be practiced:

• Never submerge a hose into buckets, pools or sinks
• Always keep the end of the hose clear of contaminants
• Do not hose spray attachments without a backflow prevention device
• Buy and install inexpensive backflow prevention device for all threaded faucets around your home