Hi,

I just had a new sump pump installed about 2 weeks ago. It works well but when it empties there is a loud rattling noise that follows. My assumption is that it is shaking the sewer pipe as the water is being forced out of the house and when the unit shuts off it creates a vacuum that can't properly release pressure so it shakes the pipes.

Does that sound right? I have looked at a few different air break valves (including Studore) but before I purchase one I want a second opinion as to what might be causing this noise. Also, I am a layman at plumbing but I have been able to tackle most plumbing issues that we've had in the past. I think installing an air break valve sounds pretty straight forward and am hoping to do the work myself.

My last concern is that I have read about a 1/8" hole that is supposed to be drilled in the pipe just above the pump. My pump is submerged and the pit is pretty deep so I can't tell if I have this or not, is it critical to the issue that I have this hole?

Thanks, Elizabeth in PA

The rattling is probably the water in the pipe flowing back down into the sump crock. Sometimes, depending on how high the pipe is, that is enough water to make the pump come on again. In that situation you have to put a check valve in. If the pump pipe is where it can freeze you drill the hole in the pipe to let the water below the check valve out to prevent it from freezing. Check valve should be at an elevation higher than the end of the pipe, that way water in the pipe above the check valve will syphon out.

Hi Harold,

Thanks for reply. I don't think it's water running back to the pit because the water level doesn't rise once the pump kicks off. It's just a really loud shut off noise. The pipe from the pit to the ceiling is about a 15' run then a 90 degree turn to the left and a 20' run to the sewer line. Do you think I should put in the AAV?

Thanks, Elizabeth

I think it's in effect "water hammer". In esscense, when the pump shuts off, the pipes shake and make a lot of noise.

If this is true, then:

A vibration isolator. I used a short piece of corrogated radiator hose in the section of pipe near the pump.

The rest of the pipe should be resonably secure.

Not all pumps require the weep hole, nor are check valves required for all pumps.

You failed to mention how far up the pump has to pump.

Sump pumps should not drain into the sewer.

Is this a sewage ejector pump?

If so, a flex coupling is still required, but a radiator hose won't do.

You should have a check valve installed near the pump. Do you have one? Regards, tom

I did mention the run of my pipe from the pit to the 90 turn as 15'. That's how far it has to pump up before going horizontal and into the waste water line.

Speedball, you would recommend a check valve as opposed to an AAV? How do they compare?

Thanks for all the help.

Elizabeth in PA

No AAV needed but yes on the check valve. I think the weight of the water suddenly stopping causes a water hammer like effect as point out by KISS.