I'm trying to get my sewage ejector pump in my basement working as it used to.

The problem is when it runs water pumped from it gushes up the water softener's outlet drain. I thought the vent was clogged (a dedicated vent ran out of the side of the house, with an elbow on top to curve it down) but I ran water down it yesterday with the hose and the water seemed to make it all the way to the pit, didn't back out of the vent or anything.

Here's a picture of the drain setup:

Drain setup

I didn't include a picture of the line from the pump because it is between the concrete and interior wall seen at the left of the picture, and I couldn't get a very good picture.

As far as viewing the actual pump, it is underneath a wooden platform that is screwed in the basement bathroom, and I haven't accessed it. It really shouldn't be clogged though, the bathroom hardly gets used, and this has happened in the past week or so. However the pump does run occasionally because some water from the sink/dishwasher above makes it into the pit despite the bathroom it not being used, which is another, less pressing issue but it might be relevant.

The pump is an Everbilt ESE50W-HD if relevant, not giving us trouble until recently, came with the house we bought a year ago. Any advice is appreciated, really thought it was just an issue with the vent.


Is it possible that it also relies on the main vent stack that extends out of the roof starting at the right of the picture? I would think an issue with that would present problems with drains in general so I expected it to be localized to this one vent or if not the vent the pump itself. Also the septic tank should not be full as it was emptied last year and there are no other indications of this such as the upstairs toilet backing up (there is no alarm).

  • Hello, and welcome to Home Improvement. Well-stated and -documented question: thanks. And, you should probably take our tour so you'll know how best to participate here. Dec 6, 2019 at 13:33
  • I would consider rebuilding the drains if possible so neither the sink nor the softener drains are "downstream" from the ejector. However, the main problem is the waste line has too small a diameter to handle the ejector pump's flow rate. Rather than stick in checkvalves all over, see if you can swap a much larger pipe for the main output after the ejector or at least after the first junction Dec 6, 2019 at 15:52
  • @CarlWitthoft Thank you for your response, much appreciated. The manual says "Do not restrict the discharge to sizes below 2 in." so my understanding was the line is sufficient, especially since it had been working up until now. I'd like to turn off the pump entirely until I can get this sorted but I don't want the pit to overflow from what it gets from the sink. I do agree that rebuilding the drains is a good idea and will consider it.
    – barthooper
    Dec 6, 2019 at 16:19
  • I think there are multiple issues here. Since I've been having this issue i've really gotten into searching about problems with pumps to see if anything might be related and I know there is a loud bang at the end of the pumping which is apparently the check valve closing. It could also be related to the sink not having a vent (it may have an air admittance valve, I can't recall).
    – barthooper
    Dec 6, 2019 at 18:42
  • Google 'quiet ejector pump check valve" one of those will eliminate the loud banging. They're about $20 Dec 6, 2019 at 20:40

1 Answer 1


If it has been working fine and this is a new problem then it seems like your waste line is plugged. Basically what's happening is your pump is pumping the waste and because it will not go through the waste line it's going up the water softener drain. The fact that water drains into the pit really isn't relevant. Also the upstairs toilet may tap into the waste line after the blockage, which is why that toilet works fine. If the vent is plugged it may cause some draining issues but no draining issues if the waste being pumped out. From the picture it looks like you have a good spot to put in a clean out so you can rod the waste line.

  • Thank you for answering. The toilet does indeed tap in after this point. It joins up with the main line that directly connects to the septic tank via a separate branch, on the opposite side. I didn't think the waste line itself was plugged because the kitchen sink and dishwasher above drain fine without the overflow occurring. To clarify, are you referring to putting a clean out where the water softener drain loops back in? Also to clarify the line continues to the right of the picture before joining up with the main sewer line that precedes the septic, in case you were referring to that.
    – barthooper
    Dec 6, 2019 at 19:04
  • You stated that the kitchen drain backs up into the pit, that's a further indication that there's a blockage. Without having a full layout of your drains and based on the info you provided if the area in the picture is easily accessed then a clean out in this area would be a good spot (right above the papers you have hanging on the wall). The blockage could be after the toilet. If it's a toilet you don't use often and there's no shower or tub you may not notice anything especially if it's a partial blockage because the toilet is only putting 1.6 gallons into the drain. Dec 6, 2019 at 20:36
  • Thanks again. That does make sense. The toilet and upstairs shower aren't affected by this because they enter the main pipe (not show, at right) from the other direction. This affects the ejector pump, upstairs sink, and dishwasher. I think the blockage is after the water softener drain, not pictured but it's a straight portion, probably debris from the sink. I hadn't thought of the kitchen drain backing up into the pit being related to this to that degree because that has been happening since we got the house, so likely the clog was already there and just expanded.
    – barthooper
    Dec 6, 2019 at 21:01
  • Kitchen sink = grease = blockage Dec 6, 2019 at 21:35
  • There is a cleanout off to the right of the picture that I forgot to mention. I took the cap off and used an auger and made it perhaps 4 feet. there are 2 90 degree bends between the cleanout and softener outlet. Nothing was on the end of the auger. I went in via a vertical cleanout under the sink and went much further in, perhaps 10 feet and got a bit of grease on the end but not very much at all yet it's the most promising lead so far. Will go in repeatedly when I get some time again.
    – barthooper
    Dec 10, 2019 at 4:31

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