Hello, this is my first post. I am a happy owner of a salt pool in Phoenix AZ. My brother called me from NCal and is having his vinyl lined pool reconstructed. Are there any regulations or can anyone recommend how far below water line the return line should be? His pool is approx. 9ft deep, it currently has one return valve and the person working on his remodel has positioned it about 9" below water line. Should he have two valves? Is this deep enough with the pool only having one valve? He has one skimmer. Am I using the right terminology? Thanks for any help or advice that you can give.

Your post caused me to get up, get a tape measure, and go out and measure my pool returns.

From the middle of the tile, the centerline of my returns are 12" below, on the money.

I'm curious to see what some of the industry guys say here.

If you winterize, you either want the returns fairly high, so they are above the winter drain depth, or fairly low so they are below the freeze line. 12" below the top of the skimmer opening is fairly common these days, though there really isn't a standard and just about any depth can be found if you look at lots of different pools.

I can't say for liner pools, but on gunite pools we always place the returns 18" below water depth. I like to use 1 1/2" pipe, and put eyeball fittings on the ends to allow for some ability to control direction. 3 returns are typical for most pools, although I do put more in if the pool is larger (and always 2 skimmers if a pool exceeds 800 square feet-more if it is really big!).

Again, I don't know about liner pools, but I would think that if I had the ability to add lines I would. A well circulating pool is a happy pool

Thanks to all who commented and provided some great information! I have spoke to my brother and turns out the person that was "attempting" to plumb this actually put it 3" below water line. Needless to say, he was "let go" from the job and Rob has employed another to handle the plumbing.

Thanks again, this is going to become my new favorite site!
Karen