Community Forums

ualdriver · 08-16-2016, 12:09 PM

While I am hooked up to city water providing adequate pressure, under what circumstances should my fresh water tank decrease in quantity?

I filled my fresh water tank while I was at the campground on day one, filling it completely until water came out of the little vent by the fill port. I don't remember how long it took, but I'd say around 15 minutes with the hose providing strong water flow. I then hooked up to city water. None of my tanks are leaking.

At the end of my campsite visit, I dragged the hose back over to the fill port just to see if I could get a few more gallons in (we were to take a long road trip with no hookups available, so I wanted everything topped off), but the tank took another 10 to 15 minutes to fill with strong hose pressure as before. Obviously quite a bit of water had been consumed from my fresh water holding tank even though I was hooked up to city water with good pressure the entire time.

How can that happen?

Old-Biscuit · 08-16-2016, 12:46 PM

Did you have your on board pump ON?

IF pump ON and city water pressure lower than pump pressure switch setting pump would run sucking water from fresh water tank.

Other than a leak.........
Siphon action thru overflow but then ground under RV/tank area would have been wet.

So either pump ran using water from tank
OR
you didn't get tank as full as you thought.........water squirted out vent line but tank wasn't completely full cause it didn't run out overflow pipe

ualdriver · 08-16-2016, 01:20 PM

Quote:

Originally Posted by Old-Biscuit

Did you have your on board pump ON?

IF pump ON and city water pressure lower than pump pressure switch setting pump would run sucking water from fresh water tank.

Other than a leak.........
Siphon action thru overflow but then ground under RV/tank area would have been wet.

So either pump ran using water from tank
OR
you didn't get tank as full as you thought.........water squirted out vent line but tank wasn't completely full cause it didn't run out overflow pipe

Yes, we ran our water pump alot as I was trying to flush out our black tank by filling it with water through the toilet flush system. The pump on provided better water flow to the black tank vs. City pressure so we ran the water pump as we ran about 4 tankfulls of water through the black tank. If the system is plumbed to feed users (sinks, toilets, etc) from the source with the highest water pressure, then I understand what happened now. Thanks!

Old-Biscuit · 08-16-2016, 04:03 PM

Quote:

Originally Posted by ualdriver

Yes, we ran our water pump alot as I was trying to flush out our black tank by filling it with water through the toilet flush system. The pump on provided better water flow to the black tank vs. City pressure so we ran the water pump as we ran about 4 tankfulls of water through the black tank. If the system is plumbed to feed users (sinks, toilets, etc) from the source with the highest water pressure, then I understand what happened now. Thanks!

Running pump draws water from fresh water tank...that is where it gets water to pump

Basic RV plumbing system