Can You Discharge Sump Pumps Into Sewers?

Bud Maxwell

Sump pumps remove excess water from below building foundations, basements, sometimes even swimming pools at the end of the season. This excess water can accumulate due to heavy rains or from ground water seepage. Where a homeowner can discharge sump pump water can be problematic, but in no case should it be diverted into the sewer system.


In almost all cases, it is against the law to pump sump water into the city’s sewer system. Sewer systems are designed to handle sanitary water based on the number of residents living “upstream,” and any increase can easily overflow the system design. Overflowing the system can either cause sewer fluids to back up into basements, or will overload the treatments plant's capacity.


Some cities offer a seasonal waiver to the local law against pumping into the sanitary sewer. Usually offered in areas of heavy snowfall, the waivers normally extend from October through the end of March, and are designed to protect homeowners from rapid snow melt. Most other cities will entertain a request for a special waiver, but the homeowner must show unreasonable hardship and prove his property is in jeopardy if water is not quickly pumped away.

Local Laws

The laws preventing the discharge of sump water are typically legislated by local governments. State and the federal officials have no interest in the locally owned waste water treatment plant and leave those regulatory requirements up to city officials. Penalty for ignoring discharge laws usually begin with a written warning, but if ignored can result in hefty fines and a few months' jail time.


Some cities allow pumping sump water into storm drains, rather than the sanitary sewer system. What’s the difference? The sewer is a closed system and designed to carry sanitary water. All water that leaves our home from sinks, showers and toilets flows into the sanitary system and ends up at the local waste water treatment plant. Storm drains are not closed. In fact, you can readily see storm drains when it rains heavily. The excess water running down the street disappears into those drop inlets in the gutter, just below the curb, and never connects to the sewer system.

Keep Discharge on Property

If you are fortunate enough to have more than a small lot, you may be able to solve your discharged problem by keeping the sump water at home. French drains can be built from perforated pipes similar to a leach field will distribute the water over large areas. If you have sloping land you could build swales that could contain excess water until it percolates into the ground. Both of these solutions, however, might require an engineer to design the proper solution.