Reuben Saltzman

Sump Pumps shouldn’t discharge into the sanitary sewer

Discharging a sump pump into the city’s sanitary sewer system is a big ‘no-no’.  While this might seem like an easier and more attractive option than running a discharge tube from the sump pump to the exterior, it’s illegal in most cities here in Minnesota when the home is connected to the city sewer.

One reason that cities don’t allow this is that during big storms their sewage treatment facilities can be overloaded.  When this happens, either sewage backs up into people’s homes, or the sewage water only gets partially treated before being dumped in to local streams and rivers (yuck).  The City of Golden Valley has a nice diagram of how this works at their web site.  They’re so serious about preventing this problem in Golden Valley that they require a sewer inspection before a property is even offered for sale.

The other reason that sump pumps shouldn’t discharge to the sanitary sewer is that municipal water departments bill homeowners for their sewer usage based on their water usage. When a sump pump discharges into the sanitary sewer, the city has no way of tracking and billing for this additional usage of the sewer.  When a homeowner discharges their sump pump in to the sanitary sewer, they’re getting a service for free that everyone else has to pay for; it’s like tapping off electricity before the meter.

If you have this type of setup at your own home, the ‘good citizen’ thing to do is to make the sump pump discharge to the exterior. In last weeks post on sump system defects, I gave some advice on how this could be done without having the line get blocked with ice during the winter.

The photos below show a couple variations of this improper setup.  The first photo below shows a sump pump connected directly to a sewer line.

Sump pump discharge to sanitary sewer

The next photo shows a corrugated discharge tube from a sump pump directed to a floor drain, which drains to the sanitary sewer.

Sump pump discharge into floor drain

Finally, one more version of this that I’ve found at a handful of homes in Minneapolis is a very shallow sump pit with a floor drain at the bottom of it.  The black corrugated tubing coming into the sides of the pit is drain tile, and the floor drain at the bottom drains to the sanitary sewer.  In Minneapolis this is a required repair item for their Truth-In-Sale of Housing program, and a permit is needed to correct this condition.

Drain tile into floor drain

Author: Reuben Saltzman, Structure Tech Home Inspections


4 responses to “Sump Pumps shouldn’t discharge into the sanitary sewer”

  1. Beaver Systems | Structure Tech Home Inspections - Part 1
    August 15, 2013, 1:29 pm

    […] to the sanitary sewer system through the basement floor drain.  As I mentioned in a previous post, storm water should not drain to the sanitary sewer.  On the other hand, if a Beaver System directs water to a sump basket with a sump pump, […]

  2. Blair L.
    October 14, 2013, 3:39 pm


    When you have different options as to where the water can be discharged to the exterior, how do you know which is the best place to position the discharge pipe?

    Any pitfalls?

  3. Reuben Saltzman
    October 14, 2013, 4:14 pm

    The discharge tube needs to terminate in a place where it won’t cause a nuisance, and where the water won’t drain back towards the property.

  4. Top 20 Home Inspection Photos from 2013 | Structure Tech Home Inspections
    December 31, 2013, 4:34 am

    […] Pump to Sanitary Sewer – we blogged about this topic earlier this year: .  This photo shows one of the craziest ways to get it […]

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