Fresh Water tank/City Water

[swingby]

This may have a simple answer but I'm just not sure. I have 2011 Montana 3556RL. We will be setting up outside Philadelphia to help with the flood cleanup.
We have filled our fresh water tank with very clean spring water. We want to use the city water (which is actually well water) hook up strictly for showering and flushing because the quality of the water coming from the well is questionable. If we use the water, hooked up to the city water connection, will it contaminate the water in the fresh water tank?

[bobbecky]

City water does not flow through the fresh tank on the way into the rig. Water only flows past the check valve in the water pump when the pump is on, unless the check valve is not functioning. So, not likely that the fresh tank water will br contaminated by city water unless you attempt to fill the tank with city water.

[JRTJH]

As bobbecky said, your "city water" is not supposed to backflow into the fresh water tank. There is a "backflow preventer" built into the pump head to prevent that from happening....

That said, there's no way to get water out of the fresh water tank without using the same plumbing runs that are filled with "questionable well water"... When you're on city water (the questionable water) and the trailer plumbing runs, both cold and hot are filled with that water, when you "turn off the city water and turn on the pump", the pump will start sending "clean water" to the plumbing runs. You've got 12 gallons to purge in the water heater and an unknown amount in the PEX lines that is "questionable water"... How long would you need to run (really spelled waste) your clean water to flush all the "dirty stuff" out of the lines ?????

What you're thinking of doing works "on paper" but in reality, you can't "push all the dirty stuff out of the plumbing runs and switch to clean water" without sanitizing the water system every time you want "clean water from the fresh water tank.....

I suppose you could "run outside and drain a bucket of clean water" from the tank drain valve, but how practical and how do you keep the bucket and the drain clean between uses ???

[Jimmy240]

I’m sure you are, but I got to ask. Are you running an exterior filter for your city water? If not, I seriously recommend one and maybe run a interior filter system attached to the faucet just to be safe.

[swingby]

Originally Posted by Jimmy240

I’m sure you are, but I got to ask. Are you running an exterior filter for your city water? If not, I seriously recommend one and maybe run a interior filter system attached to the faucet just to be safe.

Yes, we are running city water through a filter

[swingby]

Thanks for the quick response. That is exactly what I thought but could find nothing in the owner/operating manuals. I seriously doubted there were two separate lines.

[JRTJH]

This is a block diagram of your plumbing system. EVERYTHING is interconnected from the pump/city water connection to the black and gray storage tanks. ALL of the water runs through the same supply lines, so there's no way to isolate the water stored in the fresh water tank and still deliver it to the faucets.

[travelin texans]

I used 2 cartridge type filters & a RV water softener with good results every where we parked using city water sources.
The 1st filter placed before the softener with a sediment cartridge, the 2nd filter after the softener with a charcoal cartridge.
Going through this setup I also filled the fresh water tank so same quality water from either source.