Your lawn is a great reflection of the value and care that you, as a homeowner, place with your property. A well cared for lawn says a lot to neighbors, to visitors and to passersby about how well you manage not just your home, but your life. Your lawn is a great reflection of the value and care that you, as a homeowner, place with your property. A well cared for lawn says a lot to neighbors, to visitors and to passersby about how well you manage not just your home, but your life. A lawn can either be an ugly, unsightly eye sore, or it can be a lush, beautiful invitation to your home. When installing a sprinkler system into your lawn, there are of course the typical concerns that you need to consider. What kind of sprinkler heads, what size of piping to use, the control valve system, and whether or not to put the sprinkler system on a controlled timer system.

Yet one of the most commonly overlooked things that every residential lawn sprinkler system needs is an adequate sprinkler back flow preventer. In most states, it is required by law that any new lawn sprinkler system include a dedicated back flow prevention unit.

What Is Back Flow?

Back flow is when clean water that has already passed through the main water valve into the sprinkler's control valve, and then out into the sprinkler system grid of pipes, is drawn back through the control valve and back into the main water supply. There are two main methods of back flow. There is back flow pressure, and there is back flow siphonage. Both are caused by the same physical principles, but are brought about by two separate causes. Back flow siphonage is caused by a loss of pressure in the main water supply, which then draws water from all of the other pipes to bring the system's pressure into equilibrium.

Back flow pressure is usually the result of a broken or poorly installed sprinkler control valve. If an in line control valve is not installed at least six inches higher than the sprinkler heads in a sprinkler system, there will be major issues with back flow pressure.

Why Is A Back Flow Preventer Necessary?

Once water has gone past the sprinkler control valve and out into the sprinkler pipes, it is considered a contaminant. This is because of all of the particles, pesticides, fertilizer and other toxins that are found in ground soil. If this tainted water finds its way back into a potable water supply, it can be very dangerous for you, your family and for all of your neighbors. It is dangerous to drink or bathe in water that has been back flowed back into the main water supply.

What Happens If I Do Not Include One With My Lawn Sprinkler Installation?

Chances are, if you cannot provide a valid and approved permit for a new lawn sprinkler system, you will have a very difficult time ever selling your house, without taking care of the problem.

Someone Recommending Installing Anti-Siphon Valves, Is This A Good Substitute?

No. Anti-siphon valves do have an inherent back flow prevention feature, but it is only good for preventing back flow pressure issues. It is ineffective against back flow siphonage. Installing a dedicated back flow preventer will protect you and your neighbors from both types of back flow.