What backflow would you recommend?

Getting Started Wireless Flow Meter
1

Good day,

I would like to know what backflow would you guys recommend to use. I am having a hard time to find one at my local Home Depot or Lowes here in California and the reps do not have any clue why I am trying to do and they say there is no need for it if the sprinkler valves have anti-siphon.

Also, I want to mention that my house has a charcoal filter and water softener that is connected to the water main line. The irrigation water is just a T before the water goes into the house.

Thanks in advance.

2

Well, if your current sprinkler valves are the Anti-siphon variety, a backflow device isn’t needed. Do you know if you have anti-siphon sprinkler valves, or regular?

Anti-Siphon:

image
image.jpg1000×1000 95.2 KB

Standard Valve:
image

If you decide you need a backflow device, do you need pressure reducing built into it?

If not:
https://www.homedepot.com/p/Wilkins-1-2-in-Brass-Pressure-Vacuum-Breaker-12-720A/203448602?MERCH=REC--pipinstock--NA--203448602--N

image
image.jpg1000×1000 171 KB

If so:
https://www.homedepot.com/p/Zurn-3-4-in-Brass-Reduced-Pressure-Principle-Backflow-Preventer-34-975XL2S/304957724

image
image.jpg1000×1000 156 KB

4 Likes
3

Thank you so much, yes, I have the Rain Bird valves with Anti-Siphon below:

image

https://www.homedepot.com/p/Rain-Bird-3-4-in-Anti-Siphon-Irrigation-Valve-with-Flow-Control-DASASVF075/100036021

One more question, do you think I need the expensive backflow preventer (what a difference in price) if I have these 25 lbs pressure regulators on the output of each irrigation valve?

image

https://www.homedepot.com/p/DIG-25-psi-Filter-Pressure-Regulator-with-3-4-in-Pipe-Thread-D54/204758564

4

No, you should be fine. As long as your anti-siphon valves are installed above ground and higher than any sprinkler or drip emitter in the system, you should be fine without a backflow device. And those pressure reducers are typically only installed for drip lines, but they aren’t going to hurt anything on a sprinkler zone…

2 Likes
5

Thanks a lot. Very helpful information.

6

You may want to check with your local water supplier. They may give you direction as regards backflow prevention. My water district REQUIRES a backflow device.
Also, check out https://fccchr.usc.edu/list.html; USC has more info than you can imagine on this topic and a list of approved devices.

2 Likes
7

Clarification: even if your valves have backflow preventers, if you have a hilly landscape and the backflow preventers are not higher than the sprayers/drippers, you still might want to have a central backflow preventer (because gravity back pressure can keep the BFP from venting). A dedicated BFP has forward and backward pressure release. Mostly an issue if you are using manure or chemicals on the irrigated landscape - since you don’t want that re-entering your house or city drinking water.

Also, I find the integrated BFPs always leak within a few months, which is not great. I prefer a central BFP and simple valves with no BFP.

Amazon has BFPs like this: https://smile.amazon.com/gp/product/B0012QGSKC/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1.

BEWARE that many vendors including Amazon still sell parts like this that have lead in the brass fittings. California (which it sounds like you are in) REQUIRES lead-free devices. The link above is for a lead-free BFP. If in doubt, make sure it is listed for DRINKING WATER.

2 Likes