I have a sewer ejector pump in my basement that has been backing up water. This is the second time this has happened in 6 months. The water appears to be sewer water backing up from the basement bathroom or basement washer/dryer. The rest of the draining/plumbing in the house seems to be working properly. Any ideas on how to troubleshoot? Read the other posts but didn't see any advice on troubleshooting.

Well, if you run water into the pit and the pump doesn't come on you either have a defective pump or the float is blocked. If the pump comes on but does not pump out the water you have a blockage.

The rest of the house is gravity drained to the sewer and the ejector pump only handles the basement waste presurizing up to the main sewer line. Sounds like you could have a bad float, a bad float switch, a hung up float. You will need to take off the top of the ejector pit-UGH- to acces the motor and float assembly. How old is the pump?