Install a Sump Pump/Internal Drainage System

What Is It?

Even with the use of dry floodproofing techniques, water may enter a building during flooding events and from general basement leakage. Sump pumps discharge water collected in a small pit that extends through the building foundation from the basement out of the building and directly into a sewer. Internal drainage systems can supplement sump pumps by helping to capture wall and floor seepage. Sump pumps are powered by electricity, and backup generation or battery-operated backup may be necessary in the event of power outages during extreme storms. It is crucial to ensure that the sump pump has a properly sealed lid. Otherwise, moisture and other pollutants such as radon can enter the building’s basement and crawl spaces, leading to potential health problems and mold growth. Maintenance may be necessary to remove sediment and debris from the sump pit to prevent clogging.

Excessive inflow from sump pumps to sanitary sewer systems can increase the risk of sewer overflow in heavy rain events, which may result in sewage backflowing into the basement. As a result, Massachusetts has banned the discharge of sump pumps into the sanitary sewer system. A number of cities and towns around the state, including Waltham, Revere, and Braintree are currently providing free sump pump reconnections to single family homeowners.


  • Easily combined with other dry floodproofing measures (e.g. flood shields/barriers, sealants) for maximum protection from flooding
  • Provides drainage for increased water leakage resulting from sea level rise


  • Basic models require electricity to run. Power outages from storms could compromise building drainage without backup generation. Battery-operated backup pumps can be installed alongside sump pumps at greater cost.
  • Heavy flooding can overwhelm pumping capacity. Multiple backup pumps may be needed to handle additional capacity from flooding.

Regulatory Impacts and Requirements

Potential regulatory touchpoints in Boston and Massachusetts include:

  • Boston Water and Sewer Commission
    • Regulations governing the use of sanitary and combined sewers and storm drains of the Boston Water and Sewer Commission: Excessive inflow to sewer systems from sump pump may result in the Commission requiring the building owner to eliminate the source of inflow at owner’s expense.
  • Massachusetts Water Resources Authority
    • 360 CMR, Massachusetts Water Resources Authority: All inflow from sump pumps must be discharged into storm drains and not into sanitary sewer systems. Discharge may be permitted into areas only served by combined sewer systems. Note that the City of Boston uses a combined system to transport both sanitary and stormwater flow, and the BWSC has additional regulations for inflow.
  • Boston Groundwater Trust
  • Boston Public Works Department

Financing Options, Incentives, and Rebates

  • Sump Pump Amnesty Programs – In many cities and towns around Massachusetts (including jurisdictions in Greater Boston), homeowners with sump pumps that discharge illegally into the sanitary sewer system can have their pumps disconnected at no cost.
  • Hazard Mitigation Funding Under Section 406 of the Stafford Act