By Brett Wolfe, F252125
March 2012
Sanitizing the motorhome’s potable water tank and fresh water system starts with draining all the old water out of the tank and the water lines. If the water is really old, has a bad smell, or you notice bacterial growth, hook up the hose “” with the drains left open “” and allow it to run for a few minutes. Then close all the drains.
Pour a cup of regular (unscented) household bleach into your potable water hose (the white one that is lead-free) and then hook it up to your city water source. The bleach will sanitize the hose, any filter, and the potable water system.
Fill the potable tank completely and allow the water to sit in it for an hour. Then turn on the water pump, open each faucet, and allow the water to run until you smell chlorine at each tap. It will take a while for the smell to appear in the hot water, since you will be mixing the heavily chlorinated water with 6 or 10 gallons of the old water in the tank.
Let that water sit in the lines for a couple of hours, and then drain it all. Leave the tank drain open as you start to fill it with fresh water. This will flush a lot of the residual heavily chlorinated water from the tank.
Then after filling the tank approximately half way with fresh water, turn on the pump, open each tap, and allow the water to run until no chlorine can be smelled. Drain the tank again, refill it, and you are finished.
Other points:
- Store water in the tank for no more than two weeks in the summer and three weeks in the winter (cooler temperatures slow algae and bacterial growth). Do not fill the tank at the beginning of the season and leave it in there as you use campground water each time you hook up. When you do use tank water, it will be bad.
- Use a sediment-only filter for all incoming water. You can purchase 5-micron sediment-only filters at home improvement stores. Many campgrounds use well water, which can include fine bits of sand. This doesn’t pose a health problem, but the sand can cause the pressure switch on your water pump to malfunction. Do not use a charcoal filter for any water that you will be storing in the potable water tank. A charcoal filter will remove the chlorine in the water, which will allow algae and bacterial growth. Charcoal filters installed on the fresh water lines after the water pump are fine.
- Choose a filter that can be stored safely when not in use. The safest way I’ve found to store a filter is to put it in a resealable plastic bag and place it in the freezer, or to allow the filter membrane to dry completely before putting the filter away. Do not store a wet filter, particularly in warm locations. That means the “self contained” filters (unless you have an expensive bacteriostatic filter) are not a good idea. A much better choice is to obtain filter housings that use replaceable filters, which are available at home improvement stores.