We were at camp one day when we noticed water was coming out of the overflow vent for our freshwater tank. It didn’t make any sense as we were hooked up to city water at the campsite and hadn’t used the freshwater tank in a couple of weeks. So why was my freshwater tank suddenly overflowing?

Turns out, this is a fairly common occurrence. There is a one-way check-valve inside of the water pump and this often gets dislodged and stuck open . When this happens, water from the city water connection can flow backwards through the pump and into the freshwater tank.

The 2 biggest causes of this is:

Many times, the simplest fix is to cycle between the water pump and city water a couple of times:

Often times, this is enough to reset the check-valve inside of the water pump.

If it happens repeatedly, there are a few solutions to fixing it:

So there you go… if you’re at camp you notice water coming out of the freshwater tank’s vent and are hooked to city water , it very likely is that water is back flowing through the water pump. As you can see, the fixes are pretty easy.