Sump pump loud “pouring” noise after each cycle...normal? (with video)

[ChainsawLullaby]

Hi plumbing pros. A very wet Seattleite here, very stumped by my sump pump.

I have an 1920s home with a fully finished basement and an interior perimeter drain system, including a covered submersible sump pump system tucked away under tile/slab and behind my clothes dryer. All done by previous owners about 15 years ago.

Here’s what the sump pit looked like when opened after some heavy-ish around Christmas. Note that there wasn’t a check valve installed. Also note the short discharge pipe. I assume the discharge pipe ties into the sewer drain along with my bathroom fixtures since it doesn’t appear to discharge anywhere outside.

[Sump pit with old pump](https://imgur.com/gallery/vynvW4H)

We’ve had more rain here in Seattle over the last couple weeks with more in the forecast, so I had a plumber replace the old (10+ years) Zoeller pump (unknown model) with a new Zoeller 1/2 horsepower model plus a check valve (new pump and check valve not pictured).

Well the rains kept coming on cue and the new pump has been cycling often (every few minutes during and right after heavy rain) and a few times per hour (even days after heavy rain). It cycles for only about 5-6 seconds at a time, which I assume is at least partly a function of the small-ish pit.

After the quick pump cycle, a loud, long, and two-parter “pouring” noise, where it sounds like a substantial amount of water is falling back into the pit.

Loud pouring noise video of closed pit (sound on):

I unfortunately don’t have the ability to re-open the covered pit at this time to get a better video. Sorry about that.

My questions:

1) is this pouring back sound normal? Especially since I now have a check valve and since the water doesn’t have much vertical distance to travel to the discharge pipe anyway? I can’t seem to find any videos online that show this and it’s crazy loud.

2) Why would the pit be filling up with water so quickly/the sump cycling so much if I don’t hear water flowing in from the white inlet pipes (see photo above)? Wouldn’t I hear the same pouring water noise? Is it common to also drill holes in the sides/bottom of a sump pit for ground water to seep into (it sort of looks like there might be small holes drilled into the sides in my photo above)? Or perhaps the pump is simply not be clearing and cycling the same water over and over again?

The best part is this pump is one floor below where my head rests on my pillow at night. And this sucker us been hard at work, humming and pouring for several days. I’ll need to break into the good scotch to get some sleep tonight...

Any ideas?

 

[Reach4]

2) Why would the pit be filling up with water so quickly/the sump cycling so much if I don’t hear water flowing in from the white inlet pipes (see photo above)? Wouldn’t I hear the same pouring water noise?

When the water level is higher, the water coming has less distance to fall. So should make less noise.

Is it common to also drill holes in the bottom of a sump pit for ground water to seep upwards into?

Opinions vary. In my opinion, no, don't drill lower holes. I think the holes should pretty much be at the level of the gravel under the slab. You really don't want to try to lower the ground water level for the neighborhood, I think.

Or perhaps the pump is simply not be clearing and cycling the same water over and over again?

Could be. How far from the house are you depositing the water?

 

[Sponsor]

 

[ChainsawLullaby]

When the water level is higher, the water coming has less distance to fall. So should make less noise.
Opinions vary. In my opinion, no, don't drill lower holes. I think the holes should pretty much be at the level of the gravel under the slab. You really don't want to try to lower the ground water level for the neighborhood, I think.

Could be. How far from the house are you depositing the water?

Thanks. But I actually hear nothing at all - not even a drip - from the inlet pipe. At any time. So maybe that means there are drilled holes in the bottom and it’s lower groundwater, not water coming in from the perimeter.

The pipe doesn’t discharge outside as far as I can tell. I believe it’s tied into the sewer drain along with the nearby washing machine, sink, toilet, and shower. I know this isn’t code, but many things in this house or not to code and I didn’t do this work— it was a previous owner. This is also in an old Seattle neighborhood. It appears to be a professional job otherwise however.

 

[Reach4]

Your check valve could be bad.

The pipe doesn’t discharge outside as far as I can tell. I believe it’s tied into the sewer drain along with the nearby washing machine, sink, toilet, and shower. I know this isn’t code, but many things in this house or not to code and I didn’t do this work— it was a previous owner. This is also in an old Seattle neighborhood.

Parts of Seattle use a "combined sewer", and putting ground water into the combined sewer is allowed.

https://www.kingcounty.gov/services/environment/wastewater/cso-status.aspx

 

[Bannerman]

Where is the check-valve located?

If installed directly at or close to the pump, I suspect either the C-V is not fully closing or there is a leak in the discharge line. Either way, it sounds as though water within the discharge line is flowing back into the pit after the float switch can be heard snapping-off. A leak is less likely as the water seems to be flowing back rapidly, suggesting a substantial leak which would likely prevent the pump from shutting off.

If the check-valve is located some distance away, even a slight air leak anywhere between the pump and check-valve will break the suction from the weight of the water behind a closed check-valve which will cause that water behind the C-V to flow back into the pit.

The pump float switch travel distance between the upper ON limit and lower OFF limit will determine the amount of water and therefore the pump run time. If the pump is being reactivated within seconds after being shut-off, that would suggest water is reentering the pit far more rapidly than you realize from either ground water and/or the discharge line. If the pump run-time is only seconds, that would suggest a possible switch problem or adjustment will be needed.

The pipes entering from the perimeter drain will determine the depth foundation water will be drained away. Unless ground water is high at your location, foundation perimeter water is caused by precipitation. Without adequate drainage, the water within the ground will build pressure against the foundation walls. If the contractor determined there was a reason for lower drainage, the perimeter trench and drain piping would have been installed deeper below the basement floor. Placing holes in the bottom of the pit liner will most likely cause water to flow into the ground, not cause water to enter the pit.

Suggest reopening the pit so as to observe for yourself where water is entering from and how fast. Suggest also investigating the discharge line to determine where it it leading to.

 

[ChainsawLullaby]

Updated with correct video in my original post! You can now hear the extent of the loud pouring sound.

Answering a few questions:

The check valve was installed right near the pump in the pit. The discharge pipe goes straight horizontally into the floor/wall, and I assume into the combined sewer drain in that bathroom. There is no access otherwise.

Those white inlet pipes are slightly below my basement floor around the perimeter like a normal perimeter drain system.

The pump doesn’t cycle every few seconds. Rather every few minutes under/after heavy rain. Here we are several days from a large rain event (it’s Saturday, the last was on Tuesday night, with some light rain since) and it’s cycling once every couple hours.

In looking more closely at my photo of the pit, I spy what I think are a handful of holes drilled in the sides of the pit.

 

[wwhitney]

Is there any possibility the check valve is installed backwards? This theory would require that the pump pushing against the check valve has caused it to leak enough to still empty the pit.

Cheers, Wayne

 

[Bannerman]

he check valve was installed right near the pump in the pit.

Similar to Wayne's question, is the C-V installed in the horizontal section after the elbow?

Assuming it is a swing check-valve (not closed by spring force), if it was installed with the swing arm hinge pin at the bottom, that would cause the disk to remain fully open even when installed with the correct flow direction. For a swing check-valve to close correctly by gravity, the hinge pin location needs to be at the top, above the swinging disk.

See example cross-section diagram: https://www.bericvalves.com/api-603-stainless-steel-valves/swing-check-valve-class-300/

 

[Reach4]

The pump doesn’t cycle every few seconds. Rather every few minutes under/after heavy rain. Here we are several days from a large rain event (it’s Saturday, the last was on Tuesday night, with some light rain since)

That duty cycle sounds normal, but I did not listen to your video.

 

[Bannerman]

The pump doesn’t cycle every few seconds.

It cycles for only about 5-6 seconds at a time,

 

[ChainsawLullaby]

You’re misunderstanding what I’ve written.

When the pump runs, it runs (i.e., completes 1 cycle) in about 5-6 seconds.

It does not complete a full cycle and start a new cycle 5 seconds later.

It starts 1 new 5-6 second cycle every few minutes or every few hours.

 

[ChainsawLullaby]

Similar to Wayne's question, is the C-V installed in the horizontal section after the elbow?

Assuming it is a swing check-valve (not closed by spring force), if it was installed with the swing arm hinge pin at the bottom, that would cause the disk to remain fully open even when installed with the correct flow direction. For a swing check-valve to close correctly by gravity, the hinge pin location needs to be at the top, above the swinging disk.

See example cross-section diagram: https://www.bericvalves.com/api-603-stainless-steel-valves/swing-check-valve-class-300/

I will investigate this - thanks! I’d be surprised if a plumber messed this up, but maybe I shouldn’t be.

Would a spring check valve also solve the issue? If so, is it also quiet enough to not do the loud bang thing like some check valves apparently do?

What would be the correct position of the weep hole if the correct check valve/correct orientation is installed horizontally?

 

[ChainsawLullaby]

That duty cycle sounds normal, but I did not listen to your video.

That may be true for some homes. It wasn’t true for mine last year when we had much more rain. Plus, I’ve since improved my downspout drainage.

That, plus the excessive back flow, tells me it’s probably pumping mote than it should be.

Here’s the corrected video with sound if you’re curious:

Appreciate all the replies!

 

[Reach4]

It starts 1 new 5-6 second cycle every few minutes or every few hours.

If you replace that sump pump in the future, use a smaller pump.

Adjust the tether to increase the cut-on/cut-off height.

 

[ChainsawLullaby]

Thanks folks. Will report back.

 

[ChainsawLullaby]

Update: the plot thickens!


Opened up the pit. Here’s what it looks like:


https://imgur.com/gallery/s5kYpeH


The brand new 1/2 pump is working well, albeit short cycling more than is ideal at the moment. The check valve (vertical, green) seems to be doing its job.


The pit is filling up with water fast after the record rains we just experienced here in Seattle, the vast majority of which is coming from the small holes drilled in the basin (a couple are circled in blue, but they are scattered throughout and there are several below the water line). Draining the pit completely reveals water rushing in fast from the lowest drilled holes, which are well below my 100 year old, thin slab, complete with zero gravel layer or vapor barrier, or anything resembling a building code.


Right now the pump is going off about every two minutes. The ground is saturated far above normal levels and the water table is simply very high. I know there is some debate around the concept drilling holes in the basin altogether. My setup may be a bit aggressive and capturing more water than is really needed. A much smaller amount of water is trickling in from one of the white inlet pipes (the one that is not circled).


I confirmed that this discharge is tied into the combined sewer. I unscrewed the cleanout in my backyard, which is on the other side of the wall from the sump pit in my laundry room, at ground level, not 10 feet away. I put my ear to it and could hear some water gurgling down below when the pump cycled. The side sewer has been cleared and lined recently.


Here’s the catch — and the source of the pouring noise!


The OTHER white inlet pipe (circled in red) is the culprit. Unlike inlet pipe #1, I’m not seeing a trickle of water coming from this pipe as the pit fills up, at least at the current flow rate. But, as soon as the pump cycles, a small amount of water (maybe 1/2 to 3/4 cups or so) pours out of this inlet pipe and into the pit immediately after.


Huh?


This is makes me worried that there must be a break in the 1.5 inch discharge line (which also happens to buried under concrete, tile, and drywall). My current hypothesis is that there is a fitting that is loose somewhere despite it being only about 15 years old. And when the pump cycles, sending water through the discharge line, some amount escapes only to be caught immediately by the nearby perforated white inlet pipe. My hope is that 90% or more of the water is making it all the way from my sump basin to the sewer and only a small amount is escaping. However I can imagine some water is lost in the process and going exactly where it shouldn’t be going.


I think I will need to call someone with a specialty, very small scope camera, peek in the discharge line, and see what we can see. Any sort of fix is going to be very destructive (expensive) to the finished basement. I assume you can’t just line a little 1.5 inch pipe. It may ultimately not be worth it if we can also confirm that most water is going to the sewer (will require a proper scope of that too) and if I’m not experiencing major symptoms of the lost water.


What do you all think of this hypothesis? Could there be another explanation that I’m not thinking of?


(As an aside, hundreds of thousands of people in Western Washington lost power in the combined record winds and rains last night. My own power was flickering all night. Power went out two blocks away. I was on pins and needles wondering if my sump pump, which was cycling every two minutes, was about to stop at any moment and flood my newly refinished basement. Time to look into back up options, even though I am working with very little space behind a clothes dryer!)

 

[Reach4]

The OTHER white inlet pipe (circled in red) is the culprit. Unlike inlet pipe #1, I’m not seeing a trickle of water coming from this pipe as the pit fills up, at least at the current flow rate. But, as soon as the pump cycles, a small amount of water (maybe 1/2 to 3/4 cups or so) pours out of this inlet pipe and into the pit immediately after.

Is that other pipe higher than what the water level in the pit reaches? If not, it could be filling with water from the pit as the water rises, and giving back that water.

Maybe put a "test plug" in that pipe, as a test at least.

Backup options make sense. Do you have natural gas? A natural gas-powered generator is handy.

 

[ChainsawLullaby]

It is much higher than the water level/where the float switch triggers.

I’m wondering why water would come out of it only immediately after a pump and discharge cycle since the inlet pipe and discharge pipe should not be connected to each other.

 

[Tuttles Revenge]

Test the hypothesis of the broken / connected drain. Pull the power from the pump and allow it to fill up to the level of the white suspect pipe (that must be a perimeter drain that runs around your newly finished basement and likely has cleanouts in the corner- thats how i see them done in most seattle homes).. Be prepared to control the float manually. Tie a stick or something to it. Hold it down and plug in the pump. Cycle the pump a few times and see if the water from the white pipe correlates. If so, there could be a break in the line or somehow the 2 systems are tied together somewhere downstream.

Its possible that both drains are connected and when the pump discharges some is coming back through the perimeter drain.

 

[Jeff H Young]

yep its a leak, if it only drains after pump cycles. The abs goes straight out the building and then 90s up? abandon and run new or concider camera inspection