About every half hour my water pump runs for two seconds and I know there are no plumbing leaks in the RV. The water pump is from 2003 and has been let run dry with the switch on accidently  for two whole days. Yes, it still works but, is it possible it's letting water back flow to the freshwater side? Anyone ever see this problem?

Yes, I have.  The pressure in the freshwater system is bleeding off. There is a check vale in the pump head that may be leaking pressure back to the potable water tank.  The other place pressure can bleed off is at the check valve in the "city water connection".  Also check that the sink valve, toilet valve, and water heater are not leaking.   

 

I put a check valve between the pump and potable water tank.  If you do don't use the cheap plastic one; they don't last.  Get a brass one.  I sed a Camco 23303 1/2" Back-Flow Preventer - Lead Free, on Amazon, and some hose fittings with clamps.  Check these out at etrailer.com.https://www.etrailer.com/dept-pg-RV_Fresh_Water-sf-Valves-pt-Check_Valve.aspx

Mine did the same thing and filled the fresh water tank. Replacing  the pump fixed it. 

Guessing a new water pump is next on the list. Thank you much.

 

Went out yesterday to pay a little attention to the 01 work truck since it gets used more. Turns out I already did the oil and filter change and cooling system flush recently ! Took me awhile to remember what went on before vacation after watching purple hair, for a week, floatin around camp.

Edited May 28, 20222 yr by JAG1

On 5/28/2022 at 9:40 AM, JAG1 said:

Took me awhile to remember what went on before vacation after watching purple hair, for a week, floatin around camp.

Blue and black... You must be color blind... 

I'll have to request that option next time I'm reincarnated