Is it really a Sump Pump?

A couple of years ago I received a call back on an inspection I did a month or so prior. It was the middle of summer in the peak of air conditioning season. The client was unable to attend the inspection because he was moving from another state. The home was fairly new (2003-2005) and was fairly well maintained. So after his first night in the home he called me and was noticeably, shall I say, “irritated”.

“We have big problems!” I said: “Ok, what is going on.” He precedes to tell me that his sump pump ran all night long and that it is depositing ground water into his septic system and I was on the hook to fix it, “And it was going to be expensive!”. My reply: “That is not possible because you don’t have a sump pump.” He said: “Bullshit, I don’t!” I replied, “I’ll be right over”.

So I went over and tried to explain to him that the crock in his basement was only collecting floor drain water from the A/C condensate drain. He wasn’t buying it so we had to take the lid off so he could see for himself. What he had was not a sump pump at all, but a sewage ejector pump, or lift pump. This type of system goes by many names, sewage ejector pump, lift pump, effluent pump, etc. Basically the main difference is that this type of pump is only allowed to collect fluids (and solids in some cases) that must go into the main sewer drain (no ground water). The water softener system, condensate drains, and other water conditioning drains such as an iron filter must discharge into the main sewer. This type of pump is necessary when the main drain exits the home higher than the basement floor. If there is a basement bathroom an effluent pump is necessary as this type of pump has a grinder to reduce any solids so they can be pumped out. Another easy way to tell if it is and ejector pump is that it will have two pipes exiting the lid. Since it is part of the plumbing system it must be vented. The second PVC pipe is the vent.

After I told this gentleman that what he heard all night was the pump kicking on because the Air Conditioning unit was running a lot. He was sure that there was no way that the AC could produce that much condensate. It is a fact that during the height of AC season, the unit can produce 25 gallons a day. When I built my last house our air conditioner filled our 900 gallon septic tank before the electrician got the pump wired. Every time our effluent pump kicked on, water came pouring out from under the septic lid. Fun times! I call it an effluent pump here but we actually just used a standard sump pump because there are no solids so there was no need for a grinder, confused yet? People misuse these terms all the time and that often causes confusion for homeowners and home buyers.

What is a sump pump then?

A sump pump/crock is a basin that collects ground water from the perimeter of the foundation wall to reduce or eliminate moisture issues in the basement. Current building standards call for drain tile on both the interior and exterior of the footing, with bleeders through the footing at even intervals. These drains deposit any water collected into the sump system to be pumped to the exterior. At my home I dug in a curtain drain and have my sump discharge below grade, But oftentimes this discharge is above grade. One rule of thumb is to be sure the discharge is at least 6 feet away from the foundation wall, this helps to prevent the same water making its way back to the foundation wall.

So sometimes if it looks like a duck and quacks like a duck, it ain’t a duck at all, and it’s definitely not a sump pump either…



Aaron M. Zuehlke is the owner and inspector at Zuehlke Inspection Service, LLC, a full-service home inspection company serving Southern Wisconsin. Specializing in Home inspection, Radon Testing, Mold Testing/inspection, Residential Thermal Imaging, and Manufactured Home Foundation Certifications. He also manages several rental properties through Zuehlke Properties, LLC. He can be reached by email at or by calling the office at 608-931-7485.

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.

%d bloggers like this:
search previous next tag category expand menu location phone mail time cart zoom edit close