3 in. ABS Backwater Valve

Threads, seals, and valve are very forgiving. This thing will save your rear in a catastrophic rain event. Go ABS plastic, tougher in every way.

poor flapper design, doesn’t have water tight seal, flapper attachment seems flimsy. Sioux Chief procheck has a silicon tight flap seal, flapper is a separate attachment seems stronger and more water tight, plus little cheaper.

Does leak back a little bit

Product received as described.

The pro's: Sturdy. The cap has a nice, smooth action when opening or closing. Instructions are listed on the cap: "hand tighten, then 1/4"*. Flapper has a seal that works well and is removable, which is necessary if I ever have to replace the flapper seal. The con's: *hand tighten + 1/4 is actually too much! I could not manually un-tighten by hand after doing this. That's easy to correct (don't tighten too much). The real show stopper is that the flapper sits in a notched recess. Any excessive water movement could bump the flapper up and out of these notches. The flapper would then sit uselessly inside the chamber. I deducted 1 start for that design. I got around this by placing some Christy's PVC tape (great stuff, BTW) over the top of the notches. That seems to work well and water easily flows through the flapper portal, into the chamber and then out of the chamber to the promised land (the sewer). I will check the chamber once every 6 months to be sure the tape is still in place. Overall, happy with my choice and I feel this will stop the back-flow of sewer water, if/when my mainline ever clogs again. (hint: it will because I have an invasion of tree roots)