Pumped Out Water Tank into Campground System

[Zulu]

This has only happened a few times at campgrounds, but it has me wondering about some campground's water systems.

Here's what happens: I connect to campground water system and fill up my water tank. Then I switch on my water pump so that I get great water pressure. However, I leave the RV connected to campground water just in case my water tank runs dry. (Then I'd turn off my water pump and use campground water.)

99 times out of 100 this setup works fine. My water tank drains as I use water and then I fill it up again. Easy peasy.

However, a few times, like today, my water pump keeps running (unbeknownst to me) and drains my water tank -- and not into my holding tank.

Bad/missing back flow valve in campground?

[Ranger Smith]

Bad check valve at your water hose inlet.

[oldjohnt]

Zulu you and others probably know all this already,  HOWEVER for anyone who doesn't:

The RV city water hose inlet should have a working check valve so city water can flow IN but water cant flow backwards OUT. If its not holding the fresh water pump can for sure discharge water outside (subject to more below) grrrrrrrrrrrrrr.

Similar, the RV parks city water hose source/connection "often" has a back flow preventer so water can flow out and into the RV or wherever, but NOT flow back into the city water system.

Also, if your RV pump keeps running and depletes your fresh water holding tank DO YOU KNOW FOR SURE WHERE IT WENT ?? Perhaps it flowed somewhere OTHER THEN back into the city water system?? For that to happen BOTH your RV check valve would have to be bad (isn't stopping flow backwards)     PLUS     the backflow preventer by the RV parks hose barb is bad UNLESS the backflow preventer allows it to discharge to the ground but still NOT back into the water system as I've observed. Typically the city water pressure is greater then an RV pump which prevents backflow regardless …………..

If your fresh water pump is continually running and empties the tank you need to see it its flowing OUT the bad inlet check valve and if so where its going OR ELSE maybe its going elsewhere???

Those inlet check valves go bad now n then, I've repaired some by bumping the valve seat in possibly removing a piece of rust or crud preventing the seal causing them to leak back.

While there's a chance the inlet check valve may be at fault, there may be another cause.  If you unhook the city water at the RV inlet and turn the fresh water pump on its easy to see if water is discharging there. Even if it is then where is it going???? On the ground at the backflow preventer ???????????????????? or into the city water ????????????? I doubt that because the RV pump has to overcome the city water pressure PLUS there's no working backflow preventer !!!!!!!!!!!!!!!!!

I cant say from here what's wrong but by hooking and removing hoses and turning city water and the RV pump on and off I bet you can figure it out !!!!!!!!!

 John T   

[Lou Schneider]

Another consideration is backflow through your water inlet will put full water pressure on the backflow prevention valve when you're not connected to city water, but when you are connected you'll only have the difference in pressure between the pump and the incoming city water to hold the backflow valve closed.

You may have an inlet valve that seals completely when it's slammed shut with 40 PSI of pressure behind it but allows leakage into the city water if there's only a couple of PSI pressure difference holding it closed.

The simplest answer is to turn off your water pump when you're connected to city water.  Or only turn it on when you want to use that "great water pressure".

[Twotoes]

I don’t understand why you are running your pump and using the water in your fresh tank if you are hooked up to city water? I fill my fresh tank and then use city water leaving my fresh tank for an emergency like if the RV park shuts off the city water for repairs. My fresh water tank is always filled and ready to leave and hit the road or for an emergency. 

[chirakawa]

3 hours ago, Zulu said:

Then I switch on my water pump so that I get great water pressure.

 

30 minutes ago, Twotoes said:

I don’t understand why you are running your pump and using the water in your fresh tank if you are hooked up to city water?

 

[oldjohnt]

FWIW since the "city water" pressure at some parks is much less then the 50 PSI or so my fresh water pump can supply, I have at times used my stored fresh water and pump instead of the utility, but when I do I still keep my fresh water topped off in case as above the parks water is down and so I'm ready to hit the road with a full tank. However, I don't as a general practice keep my pump on when I'm hooked up at a park that has good pressure. I've seen my share of faulty or clogged up inlet check valves.

John T   

[Ray,IN]

It your water tank contents were actually pumped back into the CG water system, the CG will be in hot water if detected, as the vast majority of states water system laws require a backflow prevention device on every water outlet to prevent water system contamination.

FWIW private water well systems are just as regulated as a city water systems if they serve the public.