David wrote:

Problem: House pressure rises during the night from 40 PSI to 70 PSI.
Is incoming pressure regulator failing?

SNIP

Yes. Even the tiniest of leakage past the regulator will slowly
increase downstream pressure. The valves are quite rugged and the
leakage could simply be due to dirt accumulation. But, hey, if you
have to remove the thing to clean it you might as well replace it.

Plan "B": Leave some faucet open to drip just enough to compensate.

Jim