Plumbing pressure tested at 40 psi and dropped to 31PSI after 20 minutes. What may this indicate?

plumbing pressure tested at 40 psi and dropped to 31PSI after 20 minutes. What may this indicate?
And it holds at 31PSI? If on a pump several things would cause this. A small lerak in the suction line, **O**
A faulty check/foot valve.
I'm going with door number two. And here's why, a small leak in the suction line would bleed off all the pressure in time but a spring check/foot valve could have a spring that the spring got weak enough to hold 31 pounds but didn't stay strong enough to hold 40 or 50.
That would give you the problem that you have.

Good luci, Tom

Mcann, are you talking about a residential water well, or are you referring to a pressure test for home plumbing?

Can you give us a little more detail about this. If so, we will do our best to help out.

I only have the HUD inspection to go by and their pressure test is done with air. I am not sure if it holds at 31, not in the report. The house is on city water, not well. The foundation is slab and shows signs of (cracks) of issues. I am not allowed to actually turn the water on to see if there is a leak so trying to determine if the drop in pressure indicates a potential leak.

Thanks for your feedback.

Yes, the drop in pressure indicates a leak somewhere in the system. Could be a tricky one to find with air. If you can't get the water on, I would pump up the system with more air and try to locate the leak by ear or with liquid leak detector at all visible joints. IF the house has been without water for some time I would bet the small drop in pressure was through a faucet that had dried out washers or orings. What are they telling you to do before you can turn the water on?