Backwater valve leaking

[northpipe]

We have an inline backwater valve (IPEX 3") installed in our basement connecting to the main sewer drain. We are noticing leaking when there are big rainstorms. We suspect the valve plug is not sealing properly. Any suggestions on how to check the plug and test the seal?

Also wondering what would be typical pressure in case of sewer backups. Sewer drain is 6".

 

[KULTULZ]

We have an inline backwater valve (IPEX 3") installed in our basement connecting to the main sewer drain. We are noticing leaking when there are big rainstorms. We suspect the valve plug is not sealing properly. Any suggestions on how to check the plug and test the seal?

Also wondering what would be typical pressure in case of sewer backups. Sewer drain is 6".

Is the valve under a slab without an inspection port?

Where is the leakage?

 

[frodo]

a 10' head of water pressure is 4.3 psi


The formula for psi of static pressure is the height in feet times approximately .43 (or divided by approximately 2.33). Multiply the height of the water above any point by the area of the tube at that point and you can determine the total static pounds of pressure acting on that area. Such as a point 10' down the tube would be about 4.3 psi x pi x 2"^2 = 54 lbs approximately.

 

[KULTULZ]

a 10' head of water pressure is 4.3 psi


The formula for psi of static pressure is the height in feet times approximately .43 (or divided by approximately 2.33). Multiply the height of the water above any point by the area of the tube at that point and you can determine the total static pounds of pressure acting on that area. Such as a point 10' down the tube would be about 4.3 psi x pi x 2"^2 = 54 lbs approximately.

...damn...

 

[frodo]

...damn...

that bees on da test..10' head of water for testing dwv

 

[northpipe]

KULTUZ: the valve is under the slab but there is an inspection port. I suspect that the leak is in the plug's gasket (right above flap, see picture), then water rises to top of port and spreads from there. It only occured after heavy rains.

frodo: thanks. So to calculate my head, would I be correct if I determine the height between the valve and street level (as a worst case scenario, since my neighborhood is flat).

 

[frodo]

you should not have water backing up in your sewer during a rain.

most. 95% cities

sewer and storm drains are a completely different piping system
the only way you can get storm watr into the sewer is if the street floods, and watr drains into the man holes

 

[KULTULZ]

you should not have water backing up in your sewer during a rain.

most. 95% cities

sewer and storm drains are a completely different piping system
the only way you can get storm watr into the sewer is if the street floods, and watr drains into the man holes

But, he may be on a system where storm and sewer are one. He said only during heavy rain. The pressure of the water surge overpowering the valve?

Maybe call the municipality and ask if it is a combined system?

 

[KULTULZ]

But, he may be on a system where storm and sewer are one. He said only during heavy rain. The pressure of the water surge overpowering the valve?

Maybe call the municipality and ask if it is a combined system?

Let me rethink that suggestion...

You are saying that at heavy periods of rain, the valve is overpowered (it must be functional as it does not enter the home waste plumbing) and the actual leakage is at the inspection port cap? There is no gasket/seal on the cap?

Is it possible the home has drainage tile and instead of going to a sump pit, it was plumbed directly to the home sewer line?

No use rattling any cages until the exact cause is determined...

 

[northpipe]

Appreciate your input guys.

Kultuz, you hit the nail on the head. My theory is that the inspection port plug leaks with backflow pressure. There is a gasket on the plug, but perhaps the part is dimensionally defective or the gasket is not working? Let me know if that is plausible in your experience. If so I can just replace it, that would be the best case scenario.

I must mention we get a small puddle of water near the port, not gallons of water, and only after a major rain. The plug instructions mention it should be hand tightened, what happens if I overtigthen it?

My other theory: I have a French drain installed below the slab connected to a sump pit. My other theory is that excess water from the weeping tile overloads the drain and seeps out. I remember the contractor mentionning concerns with the minimal slope in the drain. This might explain why the water appears clear...

 

[northpipe]

And yes, I confirm the sewer system is combined.

 

[KULTULZ]

Do you know the manufacturer of the valve? If there is a gasket/seal on the inspection cap, maybe it is defective. Maybe apply a coating of plumber's grease on it before screwing down to prevent gasket distortion.

The drain tiles are directed to a sump and then discharged to the outside, no chance of cross-over?

 

[northpipe]

Valve is made by IPEX.

The sump pump is connected to the sewer drain, but there is also a Y to an outlet outside in case the sewers back up.

 

[northpipe]

Gasket looks good to me. I greased the cap, put it back in and we'll see if that helps. I'll update after the next big storm.