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Where Should a Sump Pump Discharge? Distance, Sewers and Septic Fields

Updated November 1, 2026 · General information, not plumbing or electrical advice

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The short answer: Send the water outside and away from the house. SDSU Extension suggests at least 20 feet from the house if possible, and says not to discharge into the municipal sewer, onto a septic drain field, onto a neighbor's lot or into window wells. Discharging too close to the house can create a loop where the same water returns to the pit. Local rules differ, so ask your city before you reroute anything.
Safety first. Sump pumps run on household power in a wet place. Unplug the pump before you handle it, stay out of standing water that is near outlets, a panel or appliances, and hire a licensed electrician or plumber for wiring and plumbing work. Check local codes and permit rules. This safety note is ours, not from a source.

Where it can go and where it can't

PlaceWhat the sources say
Outside, away from the houseNDSU Extension says to make sure the discharge pipe outside is not plugged and directs water away from the house. SDSU Extension says to discharge at least 20 feet from the house if possible.
Close to the foundationSDSU says water discharged close to the house percolates back to the foundation, is collected in the drainage system, flows into the sump and is pumped out again, creating a loop.
Municipal sanitary sewerSDSU says not to, and that many cities have ordinances that prohibit it. Boston says sump pumps may not discharge to the city's sewer system. NDSU says some cities allow it before March 31 for a fee.
City storm drainBoston says a dewatering discharge permit is needed from the Boston Water and Sewer Commission. Other cities may differ.
Septic drain fieldSDSU says not to. It can saturate the field and lead to sewer backups into your basement.
Neighbor's lot or window wellsSDSU says not to.

Sources: SDSU Extension, NDSU Extension, City of Boston.

How to check yours

  1. Follow the discharge pipe outside. NDSU says to make sure it is not plugged and directs water away from the house.
  2. Measure the distance. SDSU's suggestion is at least 20 feet from the house if possible.
  3. Look at where the water ends up. If the pump seems to run constantly, water returning to the pit is one cause. See why a sump pump runs every 5 minutes.
  4. Ask your city before you change where the water goes. Rules on sewers, storm drains and permits differ by city (SDSU, NDSU and Boston all give different examples).
  5. Hire a licensed plumber for any change to the plumbing. Boston says a plumbing permit is required for a sump pump installation.

Want a licensed pro to do it?

Boston's flood guidance says a sump pump and basin should be installed by a licensed professional. Get at least three written quotes and ask about permits.

Replacement and installation guideFind a licensed plumber

Common questions

Where should a sump pump discharge?

SDSU Extension says to discharge at least 20 feet from the house if possible, because water discharged close to the house percolates back to the foundation, is collected by the drainage system and flows into the sump to be pumped out again, creating a loop. NDSU Extension says the discharge pipe outside should not be plugged and should direct water away from the house.

Can a sump pump drain into the sewer?

Usually not. SDSU Extension says not to discharge into the municipal sewer system and that many cities have ordinances that prohibit it, because it can overwhelm the system and cause sewage to back up into neighbors' basements. Boston says sump pumps may not discharge to the city's sewer system. NDSU notes that some cities allow discharge into the sanitary sewer before March 31 for a fee. Ask your own city.

Can I drain it into a storm drain?

That depends on the city. Boston says a dewatering discharge permit from the Boston Water and Sewer Commission is needed to discharge water into the city's stormwater drains. We found no general rule, so ask your local building or public works department.

Can I discharge onto a septic drain field?

No. SDSU Extension says not to discharge a sump pump onto a septic drain field, because it can saturate the field, limit its ability to get rid of wastewater and lead to sewer backups into your basement.

Can I discharge onto my neighbor's lot or into a window well?

SDSU Extension says not to discharge the pump onto a neighbor's lot or into window wells.

Related guides

Sources
  1. SDSU Extension: Flooding and Sump Pumps
  2. NDSU Agriculture and Extension: Sump Pumps
  3. City of Boston: Flood Retrofits (cost and useful-life figures are the city's estimates)

Free printable: Sump Pump Fall Check

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