That sounds like the pump internal check valve (diaphragm) is not fully closing so pressure bleeds off until pump pressure switch closes...pump runs/pressure comes up/pump shuts off
Using the pump wil sometimes clear any debris etc on the check valve and allow it to reseat
OR it could be a LEAK.....minor but a LEAK
City water inlet check valve leaking....dripping
Water Heater T&P Relief Valve weeping...dripping
A small leak at ANY of the numerous fittings on Hot/Cold Plumbing lines
Place some TP at/around fittings and then check later for any wet TP
Is it time for your medication or mine?
2007 DODGE 3500 QC SRW 5.9L CTD In-Bed 'quiet gen'
2007 HitchHiker II 32.5 UKTG 2000W Xantex Inverter
US NAVY------USS Decatur DDG31