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Starting Member


Thursday, April 23rd 2009, 5:18pm

BackFlow/CheckValve How many do I need?

I am installing an irrigation system at my home in FL. My plan is to install (1) backflow 1.25" just as it comes out of the canal (water Source). Then its 100' of pipe to the pump. Do I need seperate backflows for each zone? I will be using Hunter products throughout, and I think some of the higher end rotors have a self contained backflow as well? I can see the reason for the backflow as it comes out of the canal because there is a slight hill as it initially comes out of the canal(25' @ 45 degrees). Since my system will not be connected to house/drinking water, I don't see a need for more than 1 Backflow preventer. My system will have 22 heads and 4 zones pumping directly from a canal. Is 1 backflow enough? Thanks.


Supreme Member


Thursday, April 23rd 2009, 9:10pm

Only one backflow preventer between the water source and the valves is all that is needed. And in your case, since the water source isn't a drinking water source, you might not need any backflow preventer.

The only time you have one backflow preventer per circuit is when you are using anit-siphon values.

However, this is one area where you MUST check with the city building inspector to determine what are backflow requirements in YOUR area, especially for connecting to a non-potable water source. Some cities have VERY strict ordanances that required very specific backflows (down to manufacture part numbers are specified) and require certified plumbers to install and annually test backflows. Others are extreamly generic, something along the lines of "appropriate backflow must be installed".

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