Finishing a Basement With a Sump Pump

The pit does not move

A sump pit collects groundwater from the footing drain and the pump moves it out of the house. The pit sits in the slab, usually near a wall, and the pump will need replacing at some point. A finish that boxes it in turns a pump swap into a demolition job. Plan the finish around the pit rather than over it.

Design points

• Access. Put a removable panel or a utility closet around the pit. Do not tile or carpet over the lid. Leave room to lift the pump straight up and to reach the discharge pipe and check valve.
• A sealed lid. A pit with a gasketed cover limits the damp air that escapes from the pit into the room. EPA's mold guidance says to keep indoor humidity below 60 percent, ideally 30 to 50 percent.
• Power. Ask the electrician for a dedicated outlet that the sump alone uses. The pump is the one appliance whose failure you notice only after a flood.
• Finish materials. Choose flooring that tolerates water near the pit. See the subfloor guide.
• A noise plan. A pump that cycles in a rec room or bedroom is audible, so a wall with insulation beside the pit helps.

Where the water goes

The Illinois Plumbing Code separates two kinds of pit:

“Sanitary wastes that cannot be discharged by gravity flow shall be discharged into a gas-tight, covered and vented sump from which the waste shall be lifted and discharged into a sanitary waste drain by automatic sewage ejection pumping equipment.”

Illinois Plumbing Code: sump and ejector rules

A footing-drain sump cannot receive sewage, and sewage from a basement bathroom needs its own covered and vented ejector pit. See the sump versus ejector guide. For the discharge, the City of Rockford's stormwater Technical Guidance Manual says “Redirecting sump pumps to a sanitary sewer system is not allowed.” The manual is a 2015 federal court exhibit, so confirm it is still current with the city (City of Rockford, Technical Guidance Manual (2015 court exhibit)). That rule matters in older basements where the pump was once tied to the house drain.

Permit angle

Loves Park counts a sump pump as one plumbing fixture opening at $15.00 in its fee schedule (City of Loves Park, fee schedule effective 2/15/2018). If your finish touches the sump, include it in the plumbing scope on the permit.

What a pump costs

These are national guides. A battery backup or a second pump is an upgrade many owners choose when they finish a basement, since the finished space has more to lose. We did not find a Rockford-specific price for it. See the cost page.

Test it before you cover it

Pour a bucket of water into the pit before framing and watch the pump start, discharge and shut off. Walk the outside discharge line and confirm it ends away from the foundation. If the pump runs constantly in dry weather, that is a water-source question for the waterproofing guide.

Questions to put to the plumber

• How old is the pump, and what is the check valve condition? Replace both before they are boxed in.
• Does the pit have a sealed lid, and can it be accessed after the finish?
• Where does the discharge run, and does it end outdoors away from the foundation?
• Is there a battery or water-powered backup, and what does it add to the price?
• Is the pump on its own circuit that the electrician has labeled?

Why the pump is part of the inspection

The sump is plumbing. In Loves Park it is priced as a fixture opening, and in Rockford it is part of the stormwater rule on where the discharge may go. If the inspector sees the pit during a rough-in inspection, the discharge route is one of the things that can be checked. A finish that moves, covers or ties into the pit without telling the office can cause trouble at final. Say what you plan to do on the permit.

Where to go next

This guide sits under Basement walls and moisture. Every price on this site, with its source and date, is on the basement finishing cost page. If this topic is on your list, these guides cover the neighbouring questions: Sump Pump vs Sewage Ejector for a Basement Bathroom, Waterproofing a Rockford Basement Before Finishing, and Subfloor Options for a Basement Slab.