Install a basement sink pump by screwing the pump onto the threaded portion of the basket strainer and connecting pipe from the pump to an overhead drain. The plumbing includes a ball valve to regulate the flow and a check valve to prevent water from flowing back into the pump.
The water flow from most faucets is 3 to 4 gallons per minute, but the under-sink pump has a much greater capacity. Installing the ball valve slows the flow from the pump so that it removes the water without several starts and stops each time the faucet is open, reducing the life of the pump. The check valve prevents the water the line from flowing back into the pump and activating the switch repeatedly.
Most of the drain systems in a home use gravity to move waste from fixtures to the septic tank or sanitary sewer line. Basements are below ground, so gravity flow does not work. The under-the-sink option is a good choice when only installing one fixture in the basement.
If the basement includes a toilet, the installer plumbs the sink drain using normal gravity flow to a blackwater sump. This sump is equipped with a special pump for moving raw sewage from the basement to the sewage disposal system.