Distance from pump to place check valve

As close as possible. Otherwise, if you have to pull the pump you will have a lot of waste to deal with. Mine is 30" above the lid and offset to the side using a 45 elbow.

Hi MP

We usually install the check valve above the ejector pit a couple feet. If you install this check valve (required), check the ejector pump manufacturer's instructions and see if you need to drill a 5/32" hole in the pump discharge pipe (level with top of pump and drilled so water will shoot out of the pipe at a downward angle) to prevent AIR LOCK of the pump, OK?

Good luck!

Mark