Canplas (CANPE) 223281W

Very simple design and works fine preventing back flow from our grey water waste tank we have in our RV. Basically has a rubber flap inside on a hinge. When water runs through it to drain, the flap is pressed open and lets water drain. If and when water flows backwards, negative pressure will cause the flap to press against the hole creating a plug so water cannot go back up the pipe and contaminate the sinks and tub areas. Has a cap which screws off to clean any debris which may prevent the flap from making a seal in the event of back flow.

I wanted to replace our old plastic utility sink with a smaller vanity type sink. High output washer would push water up into sink at the waste tee and plumber recommended not using a back flow preventer as there is a chance of the flapper getting hung up and failing. The ability to open and clear it periodically solved the problem completely. Perfect solution and easy to install on waste pipe

This was exactly what I was looking for and would never be able to find at a big box store. The waste gate will only work on a horizontal installation. I installed mine directly under a sink that is connected near a toilet that has a tendency if it gets clogged to back into this sink pipe. The gate will mitigate any backflow. It's a simple design with a clean out screw top. Installed with no major issues.

Works great for its intended purpose. I had a cheaper/smaller version with no clean-out access installed before I replaced with this one. What a difference! My drain clears much quicker and now I have access to clear any debris that may get caught in it. I have an older home and the genius who plumbed it went from a large diameter tub drain upstairs into a smaller diameter sink drain downstairs so inevitably if I ever use my tub as a soaker and then drain it water backs up into the downstairs sink. This backflow preventer solved this issue. No more overflowing sink. One star knocked off for the high price. This is all plastic with a piece of rubber, doesn't cost much in materials to make it but sadly there are copy cats out there that lack in quality compared to this one, company must be aware of this as prices it accordingly.

This simple product is the best designed of the lot. I installed a utility sink last year in the basement, with a 1-1/2"drain, and I recently got concerned about the possibility of the sewer ever flooding the basement through that sink since it's well below the manhole in the street outside. I did a fair amount of research and decided to just protect that one sink and not the upstairs fixtures (do a little Googling and you'll see why).Now, a backwater valve needs to be pitched more than the 1/4"/foot than a drain line does. Thankfully, this one has the pitch built in and there's no need to do any careful measuring. I cut the existing pipe with a sawzall -- extremely awkward to get at it but it did work -- and even though my piping is pretty rigidly mounted in the area I managed to pop this in (wet PVC cement is a great motivator!). Checked the operation of it and all is well. Now I don't have to stress as much about the basement possibly flooding through the sink.This is easy to do yourself. At first I was a bit chicken and I was going to hire a plumber to put it in. Then I got some quotes and the cost was insane. Easy to do yourself and takes all of five minutes.

I bought a new LG washer and hooked it up as always overhead in my basement and out to a dry well. It's up about 6 feet from the floor. The washer manual states it will pump up to 96" HOWEVER, what they don't tell you is the washe has an anti siphon device in it and no back check in the pump. So I disconnected the anti-siphon hose in the machine, plugged it off, and it worked. HOWEVER, when the after the pump would shut off, all the water in the hose would drain back to the pump, if at that moment the kitchen sink above was draining above the water would run into the washer. I never have this problem with the whirlpool washers for 15 years here. Anyway, if you want a washer in th basement without a laundry tub or ejector pump, this valve is the answer for you to drain into your sewer line. There is no resistance for the washer to pump thru this valve and nothing is going to flow backwards thru the valve. I was concerned about lint plugging this up, has a big cap and smooth edges on the flapper, I don't see that ever happening with this valve.

Very good product just what I was looking for. After I installed a new sump pump the higher flow/pressure was backing up water into the kitchen sink above. This totally eliminated it. Seems like a well made product.

The flap for the valve does not seat properly and will not prevent the back flow of water unless the pressure is high. I connected and elbow to the backwater valve with a two-foot riser, poured water in the riser and the water flowed out around the flap valve. While the valve is good in concept, it did not function as advertised.