Check Valve for Bird Bath Fill Line

I have a problem with tubing that I have running to two bird baths, one in the back of my lot (higher) and one near the house (lower). A valve opens several times a day for a couple minutes, sending water through the buried hose, which then T-s off, one to each bird bath. I have flow limiters in 1/4" tubing going to each bird bath to limit the flow, and it works great.

Except - after the valve shuts off, the back/high bird bath loses water quickly, and the one near the house overfills. I’ve determined, I think, that water is siphoning from the higher bath to the lower, draining the high one. That being the case, I figured I need a check valve (one-way valve) near the back bird bath to allow water to flow to the rear bird bath, but not siphon back to the other one.

I made the assumption that a backflow preventer was the same as a check valve, and bought a
Rain Bird HT075BFFS - Drip Irrigation Backflow Preventer. I was getting ready to install it, and tested it, by blowing through it one way, and then the other, and sure enough it allows air flow one way, and not the other. But it worked backwards to how I thought, allowing air flow from the downstream line, and preventing it from the supply line. I read a bit about it, and realize it must work differently than a normal check-valve, and won’t work for my purpose.

That said, has anyone used check valves in their drip systems? If so, what valve did you use? I see Rain Bird has a 2 GPH Check Valve Dripper but that would take an hour or so to fill the bird bath. Amazon has a bunch of check valves, but they’re for fuel systems and other stuff.

Can you just get the fill tubes up above the water level in the bird baths? That air-break will prevent any siphon as well. Otherwise something like this might work…


Uh, yeah, that would work. I was just looking for something more complicated that I had to buy and have installed. LOL!

Sometimes we engineers make things just a bit more complex than necessary. Your solution would still allow the water in the line to siphon back, but not the water in the bird bath, and that’s what’s important.

This is a real DUH moment for me. I really do appreciate you straightening me out. Now I just have to make some little holder for the staked bubblers I have to turn them into mini fountains, that will NOT siphon back.

Thanks for your prompt response! Does anyone need a Rain Bird Backflow Preventer??


You may need a check valve just past the tee on the side going to the higher bird bath. This would keep the line water from draining back out of the line into the lower bird bath.

Emphasis on the “sometimes!” :slightly_smiling_face: I’m an ME also and while I’ve certainly “over engineered” my fair share of projects, most of the time we get involved because there is no clear, simple answer.

Anyway, I’m glad I could help!