Backflow preventers are an important component to your backyard sprinkling system. Without these, municipality drinking water would become contaminated. A backflow preventer is a device that allows water to only run in one direction in your pipes. But why is a backflow preventer important?
Let’s say you have your garden hose turned on and you are filling up your swimming pool. Several blocks away, a water main bursts. Suddenly, you have lost all water pressure to your home. Since water runs down hill, the water in your pipes begins to flow backward to where there is less pressure, or to the lowest point in all the pipes. If your hose is still in the pool, it may begin to syphon water out of the pool, through the hose, and into the pipes in your home. If left long enough with the low pressure, the pool water may enter the pipes under street and into the neighborhood. If you have a neighbor whose house is lower than yours, it can even enter their pipes and if they get a drink of water or take a bath, the pool water may end up coming out of their pipes in their house.
This isn’t a pleasant scenario for anyone involved. In order to stop this from happening, backflow preventers are installed into the water system. Backflow preventers allows air to enter the pipes if there is a loss in pressure, stopping the syphoning effect and the backflow of the water.
The State of Utah requires each city or municipality to adhere to state regulations and implement a Cross Connection Control Program. Part of this program requires homeowners to install a backflow preventer on their sprinkler system and anywhere secondary irrigation water and culinary water pipes may meet. The backflow preventer should be installed right after your stop and waste valves. It needs to be a minimum of 12” above grade, installed in an accessible location where it will never be submerged in standing water, and protected from freezing.
In northern Utah, the best way to ensure that the backflow preventer does not freeze during the winter is to remove it completely and store in a warm location. Sometimes this is as simple as removing a couple of screws, other times it may involve much more than that. Removal of most backflow preventers can be accomplished with these steps:
Turn off the water to your sprinkler system at the main valve or stop-and-waste.
Drain the water from the back-flow preventer by opening the test cocks (there are 4 test cocks on the side or top of your backflow preventer). To open them turn the little screw ¼ of a turn.
Turn the valves on either side of the assembly ¼ turn so they are neither completely closed nor completely open.
If your backflow preventer was installed with unions, you can remove it and store it in your basement or garage for the winter. After you take it off, make sure you drain the water from both sides, open the test cocks and close the valves ¼ turn.
If the backflow preventer isn’t easily removable, make sure all valves are open 1/2 way to allow as much air into the lines as possible and reduce the water in the pipes. You can also wrap the back-flow preventer with old towels, blankets, or other insulation to further protect it from freezing.
If properly winterized, your back-flow preventer should be able to sustain the cold winter months, even if it is outside.