sump to a storm drain

Where to Discharge Sump Pumps

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How do I get rid of the water pumped by the sump pump? This article explains how and where to route water that is being pumped out of a building by a sump pump.

  • Where should sump pumps discharge their water? Is it ok to pipe the sump pump to the building drain system?
  • How to inspect & maintain sump pumps to remove water from buildings or to prevent basement leakage or crawl space water entry

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Where does the sump pump send its Discharge Water?

Sump pumps, which we discuss on this page, are designed to remove unwanted water, such as surface or ground water that leak into a building. But the sump pump system will be ineffective if the water it discharges is routed where the same water simply leaks back into the building. The sump pump installation may also be improper or even illegal in some communities if it discharges into the sewer system.

  • sump pump into storm drainIn this photo at left a temporary sump pump discharge line has been left on the basement floor - no good destination has been assigned to sump outlet hose.
  • If this sump pump is called-on to operate in this condition the building will simply be flooded.

Sump pumps that have been added to an older structure often pump their discharge to the ground surface where it runs to a storm drain or area drainage setting.

If you have such a system be sure that the sump pump discharge empties where it meets these criteria:

  • The water leaving the sump pump should be discharged to a location where it does not flow back towards the building. Otherwise it may simply cycle the same water endlessly, possibly even undermining the building foundation

  • sump to a storm drainWater discharge from a sump pump must go to a legal destination. In the photo at left we're emptying the sump pump via a small diameter (Limited flow capacity) to a local storm drain.

    This might be legal and fine in the summer for an unusual event, but this is not a reliable, permanent sump pump installation.

    As this system was found in Maine, we can expect it to freeze or simply not work in winter or early spring when it may be most needed.

    Discharging onto a neighbor, and in some communities, discharging into local storm drains, may be prohibited and are certainly a bad practice.

  • In freezing climates, the sump discharge needs to be protected from freezing or the system may not work when most needed. A long sump discharge line outside, especially one with minimal pitch or slope, is likely to freeze up in cold weather.

    We've inspected homes where the sump pump was running continuously but not moving any water because its discharge line was blocked by ice. This condition permits water to rise in and even flood a building.


Continue reading at SUMP PUMP INSPECTION or select a topic from the More Reading links or topic ARTICLE INDEX shown below.


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SUMP PUMP DISCHARGE at - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

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