2. Inspect the check valve
If its internal flap doesn’t swing freely, flush it out, and if you see mineral deposits, soak it in vinegar. Make sure its arrow points up when reconnecting it to the discharge pipe.
Sump Pump Installation in Basements, Crawl Spaces, and Exterior Drainage
3. Test the float switch
Pour a few gallons of water into the sump. If it comes on and sucks out the water, the switch (and pump) are good to go. If not, repair or replace the switch.
4. Exercise the outlet
Per code, a sump pump has to be plugged into a GFCI receptacle. For your safety, press its test and reset buttons.
5. Got a backup battery?
Top up its cells with distilled water, as needed.