Check Valve

[Jim Robinson]

Does this look like a sewer back flow check valve to you? There aren't many of them here, but that is the most likely function of this valve.

[James Duffin]

It looks more like a manual valve looking at the big nut on the top. It also looks like the bolts that hold it together have been removed so it could be being used as a clean-out access.

[Ron Hasil]

THat is a backwater valve, that needs to be hand cranked to close. There is a round handle that fits ontop of the square . Some of these do have a check valve built in as well. The one pictured does not though.

What you have is just a plain old gate valve. The drawing is what a true backwater valve looks like. The pic is just a gate valve.

[Jim Robinson]

Thanks. Why would you want a gate valve on your drain line? I guess if you were home and noticed sewage coming into the basement it could come in handy. Or maybe, they closed it if they were going to be away from the house for an extended period of time? This house would have been susceptible to a backed up main line flooding into their basement.

[H.G. Watson, Sr.]

Could be a float or a swing check valve installed also (upstream) in addition to a Shear-Gate valve. There are combination Shear-Gate and Swing-Check Valves.


Thanks. Why would you want a gate valve on your drain line? I guess if you were home and noticed sewage coming into the basement it could come in handy. Or maybe, they closed it if they were going to be away from the house for an extended period of time? This house would have been susceptible to a backed up main line flooding into their basement.


"Anyone who has ever experienced flooding caused by a reversal of sewage flow never wants to be confronted with a reoccurence. Damabe is extensive and generally uninsurable. Backwaer and its attendant problems must therefore be considered in terms of adequate control and prevention by indiviuals responsible for the design and construction of buildings. To overlook the possibility of backwater or underestimate the destruction and unsanitary conditions that will result from uncontrolled backwater would be a grave mistake."

Yes, if on public sanitary system, most likely it was intended to be closed if the home was to be unattended, or if conditions warranted it be closed while occupied (heavy rains, flooding, or if no public or shared sanitary system, such as when servicing a septic tank, or if overhead - when pump quits/power outage, etc.).

See attached from JOSAM (one such mfg) for some good, basic info. You could type "flood control backwater valve" (without the quotes) or even just "flood control" or just "backwater valve" in your favorate search engine for more.