5 Common Questions About Sump Pump Discharges

We sometimes get client questions about sump pump discharges so we thought it may be of use to write an article to answer the most frequently asked questions in that regard.


1. Can you connect your sump pump line to the sewer?

This is, by far the most frequently asked question.  The folks who are asking this are usually trying to find a solution to the flooding that discharging sump pump water into a yard can cause—namely flooding of the discharge area. 

Sometimes the discharged water just soaks right back into the area next to the foundation and just keeps pumping out only to soak back in over and over again.

The easiest solution (if it were legal) to this problem would be to hook the sump pump line up to the sewer. Unfortunately, this is not legal. 

The folks who treat the sewage in our communities have a limited capacity to do so.

Back when sump pumps were hooked up to the sewer, they became inundated whenever it rained due to all the water from sump pumps being discharged into the sanitary sewers.

The only thing they could do to keep from overwhelming the treatment facility was to open the floodgates and discharge a mixture of raw untreated sewage and storm water into the local aquifers, including rivers (and even Lake Michigan). 

In order to minimize the pollution of waterways, laws were passed to make direct connection of sump pumps to the sewer illegal. Code enforcement officers in many communities were tasked with ensuring that all sump pumps within their boundaries were permanently disconnected and made to discharge to exteriors of homes.

2. How far from the house should the sump pump discharge?

The short answer is – far enough that the water does not run back into the sump pit. 

This can be accomplished by “shooting grades” in your discharge area to determine at what pint in your yard water runs away from, rather than towards, the home. 

Most homes are built and yards graded to insure water flows away from the home but over the years, many yards have eroded and caused what appears to be a very difficult problem. 

There are several solutions for this issue, so if you have encountered a grade problem at your home, give us a call and we’ll do our best to solve that issue for you.

3. How deep should a sump pump discharge line be?

The answer depends on how deep the frost line is in your area. The ideal depth is at or below the frost line. 

Unfortunately in our area, that depths is 5 feet and most lots don’t allow for that kind of depth when installing an underground discharge line. 

One “solution” to this problem is to run the discharge line as deep as possible while installing an air gap at the point of discharge.

The theory behind this installation is that the line will freeze for only a short period of time in the winter (when it is least likely to receive discharge water because the ground is frozen). 

Because it will freeze for a short time, the air gap will allow any pumped water to overflow onto the ground around the discharge pipe which will prevent the pump from burning up due to an ice blockage in the discharge line.

Yes! Plumbing has installed many such lines in the area with, good success.

4. How to find a sump discharge line?

Some answers are pretty simple.  We’ve been asked how to find a sump pump discharge line.  This is a logical process which anybody can follow.

It starts with locating the sump pump in the basement or crawlspace.  This will be in a pit that looks like a round garbage can buried in the floor. You will see a steel or plastic lid on the can. 

Locate the pipe that is coming vertically out of the pit. Trace the line as far as it goes and you will see it eventually go through an outside wall. 

Make a mental note of where you are seeing this in the basement or crawlspace.

Then go to that spot on the outside of the home and locate the same pipe coming through the wall. Trace it from there to the end. 

If that pipe goes underground after it comes out of the outside wall, then look in the yard for a spot where the water is flowing (you can run a hose into the pit downstairs to if the pump has no water to pump).

If you still can’t locate the line, Yes! Plumbing can help with an electronic locator. 

5. How long can a sump pump discharge pipe be?

As long as your property has a downward slope from the point of discharge to the end of the pipe location, it can be any length that you want, subject to engineering requirements for size and drain capacities, etc. 

Again, in our area, freezing becomes a big consideration. Keep in mind that the shallower the pipe in the ground, the more quickly it will get below freezing in the winter time.

The temperature of the discharge water coming out of your sump pit will be well above freezing but as it travels down the underground discharge pie, it cools down and if it doesn’t get far enough before freezing, your discharge line will plug up with ice.

The best rules of thumb to prevent freezing and plugging of the discharge line are: bigger is better, deeper is better and shorter is better.

So bury the line as deep as you can; make it as short as you can while ensuring the water won’t circle back to the basement, and don’t scrimp on materials—a few extra bucks spent on bigger pipe and fittings will pay off in the long run.

And if you are not qualified to do the work yourself, be sure to hire a licensed bonded contractor who has the expertise and experience to do the job correctly.


As always, Yes! Plumbing is available 24/7 to help with any plumbing projects or issues you have.