Ditch the check valve in basement?
For context, my wife and I recently moved in with her 94-year-old mother. The basement has a small blackwater/sewage ejector tank with a pump system. Each time the pump activates, the check valve makes a very loud “thunk” sound from water hammer.
The purpose of the check valve is to prevent sewage from flowing back into the basement plumbing fixtures, since the basement bathroom is the low point in the system.
Last week, while I was taking a shower, the water stopped draining. I tapped on the check valve and everything immediately began flowing again, which made me suspect the valve may be sticking intermittently.
That got me thinking about whether the piping could be redesigned to eliminate the need for the check valve entirely. One idea I had was creating a vertical loop configuration so the basement fixtures would no longer function as the system’s lowest point, while still preventing backflow.
The following AI-generated illustrations show the concept before and after the proposed redesign. The loop is in the bathroom above the “pump room”.
I live in Maine, against code? Am I missing something?