Question about a drain and interesting example of iron ocre.

[Eli Smith]

hi,

I have a question about an unusual drain system I saw in a house built in 2007.
First, I saw a hole in the slab, there was no sump pump nor pit.
In it was a backwater valve and water flowing somewhere under the slab and, as you can see on the picture, the water does not flow in a pipe, but in a homemade hole.
I tried a few plumbing systems, but the used water did not seem to pass by the drain.
So it seams to have something to do with the french drain, but definitely homemade.
Where ever the water goes, the back water valve does not protect the water from coming back in the house from the hole in the slab, so I am asking to have it checked by a plumber, however, does anyone know exactly what is this for or it's purpose?
Could it simply be the access to the main water valve but they forgot to put the cap on it?

Also, this is a good example of iron Ocre.

Thanks for the help.

[Joe Hendrix]

What I find interesting is the shape of the imprint in the concrete. It looks suspiciously like the footprint a removed sump pump would have made. Could there be any way that a sump pump was put there to remove water that built up and pushed it somewhere else?

[Steven Turetsky]

In my neck of the woods we call that back-flow preventor or a check valve. If water is flowing through the valve it will not close. with gravity and water flowing in the opposite direction it should close... they sometimes fail. Access is advisable for clean out in case something gets stuck that may prevent it from closing. I normally leave the concrete slab thin above these valves in case the entire valve has to be replaced.

If water is constantly running through it, there must be water constantly building up in your drainage system.

It's hard for me to tell in the picture, but it looks like it "flap" hinge may be broken. If that is the case, the entire valve has to be replaced (if they want it to function as intended).