Sump pump discharge rules in Mount Prospect, IL
Illinois · Last checked November 2026
Mount Prospect requires sump pump discharge to end no more than 5 feet from the foundation and at least 5 feet from the lot line. A neighbor can waive the lot line rule in writing, and older setups are not grandfathered.
Key facts
- Distance
- No more than 5 feet from the foundation, at least 5 feet from the lot line.
- Waiver
- Written permission from the adjoining owner.
- Older homes
- No grandfathering.
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How it works
Almost every city bans sump pump water from the sanitary sewer, because clean water overloads treatment plants and backs sewage into basements. Where you can send it instead varies: some cities ban street and curb outlets, some allow them in summer only, and some require a storm sewer connection.
- Make sure the pump does not drain into a floor drain, laundry tub or sanitary line.
- Route the discharge to your yard, far enough from the foundation and the sidewalk that it soaks in.
- Do not run hoses across the sidewalk or drill the curb unless the city allows it in writing.
- Ask the city about a storm sewer connection permit if your yard cannot absorb the water.
What it costs
Rerouting a discharge line or adding a buried outlet is often a few hundred dollars. A storm sewer connection or a new sump system costs more and usually needs a permit.
More in Illinois and nearby
- South Elgin Allowed with a permit
- Sugar Grove Street discharge limited by season
- Urbana Allowed with conditions
- Wadsworth Allowed with conditions
- Perry Street discharge limited by season
- Waukesha Allowed with conditions
- Kenosha No street or curb discharge
Sources
Last checked November 2026. Programs open, close and change funding every year. Confirm with the city before you hire anyone. Report a change.