Camping and RV Articles > How to winterize your Fresh Water System

How to winterize your Fresh Water System

  • How to winterize your Fresh Water System:

Before winterizing the water system, I usually run about 10 gallons of water
(hot if possible) into both the gray water and black water tanks. Pour in a cup of
Clorox and some detergent in each. Drive around for about ten miles and stir everything up.
Drain the tanks and rinse thoroughly. This usually keeps them fresh over the winter.
Lubricate the "stems" of the gray and black water tank valves with some 30 weight
oil on your fingers. Work the stems in and out a few times to lubricate the guides.

To winterize your system, purchase a "blow-out plug" to screw onto your
city water connection. Drain your water tank, lines and water heater. Close all drains
and faucets. Connect a compressed air supply to the adapter using an air chuck.
Limit the air pressure to maximum 30 pounds. Open one faucet at a time so that all
the air is directed out of one faucet.

Start with the faucet closest to the pump and move further along the line as that one
dries out. *Remember to keep the faucet open until no water comes out*. Don't forget
the toilet and the shower. After blowing all the faucets clear, disconnect the air supply.

Then, either:
a) Put 2 gallons of RV antifreeze in the fresh water tank and run the pump and open each
faucet a little bit.
b) Purchase an inexpensive but permanently attached lashup that uses your water pump
to suck the anti-freeze directly from the gallon bottles and pump it on through your system.
c) Disconnect the hose that brings water from the fresh water tank to the input side of
the water pump; disconnect the end at the pump.

Now connect several feet of new hose to the pump, and put the other end into the bottle
of antifreeze. Let the pump pull the antifreeze out of the bottle and push it
into the pipes. This gets antifreeze everywhere except into the fresh water tank.

I also suggest you install a by-pass on your hot water tank, (Camping World #7204 @ $16.98,
or equal) to save six gallons of anti-freeze. Consider the toilet flush pedal a
"faucet" in this description (See below) You also need to remove the water
from the sink traps. I found the best way to do this is to get a "turkey baster"
and attach a short length of small diameter hose to the tip. Draw the water from the traps and
pour in about one-half cup of anti-freeze, either potable or automotive.
You can drain the sink trap by unscrewing the "U" section, but that wont
work on the shower drain.

The question then remains as to what do you do for the water in the hot water tank.
You can try the following: First, open the relief valve at the top and open the drain
cock at the bottom of the tank (this should be found on the ouside of your RV).
Wait until no more water comes out, then either:

a) Get an air mattress adapter for a standard compressor.This adaptor will fit into
the drain outlet of the hot water tank so that you can blow air through it to
remove the remainder of the water through the relief valve


b) Pump in antifreeze* until the liquid coming out the drain cock is as pink as what
is going in to the pump.

In either case, leave both the relief and drain valves open for the winter to ensure
no freezing damage.

*Any suggestions on how to pump the A/F into the Hot Water Tank would be greatly appreciated.
(It contains Ethelyene Glycol which can be (is??) fatal to humans, pets, etc).
Use only specially formulated RV antifreeze which can be found at most RV/Boating supply
stores. (Hint: Wallmart sells it also...much cheaper).

Also, here is a little added bonus on cleaning the Black Water Tank:

Here is a tried and true method of cleaning the Black Water Tank, sort of invented by
a roadside cafe waitress in the 50's. When that waitress burnt the bottom of the glass
coffee pot, no amount of scrubbing would get it clean quickly. The waitress simply
put in some ice cubes in the pot, swirled it around, and wa-la, clean coffee pot! The same
method will work to clean the inside of the blackwater tank.
Start with the tank empty. Fill it with water just below the first sensor's level.
Then add 3-4 bags of department store ice cubes through the toilet. Drive the vehicle
immediately for 10-15 minutes, ensuring you go up and down hills to swirl the ice around.
The movement of the cubes will clean stuck toilet paper and feces from the sensors, and give
the tank a great scrub without damaging the seals or costing alot of money (about $3).
Those commercial sensor cleanors cost over $10 and don't work very well. The bleach method
does not "scrub" and thats what you need to clean the sensors. Give it a try.
Oh, yea, if you live in a climate that's hot, the colder the ice, the better. Most dept
store freezer's temps are just barely cold enough to keep the ice frozen. Place the bags
in your home freezer to get them nice and hard. You'll get more "scrubbing" minutes that way.

  • Other Opinions on the Subject:

Blowing out the system actually works better if you start at the faucet farthest from
the pump. Don't forget to cover the faucet before you open it, saves on cleanup.
Do Not put RV antifreeze in the fresh water tank. The tank drain is not on the bottom,
it is 3/8-1/2" up the side. Unless the tank has been allowed to dry completely
you will dilute the RV antifreeze and significantly reduce it's effectiveness. With a
dry tank it will take quite a bit more than two gallons to do the job. Options b and c
are the only way to go.

A water heater bypass is definitely the way to go. However you will find several different
ones available at many RV accessory stores for much less than $16.98. It has been our
experience that when you fill the fresh water plumbing with antifreeze the overflow
is more than sufficient to protect the various P traps We have not found it necessary
to make any additional effort to remove the remaining water from the water heater.
What's there will freeze but it does not expand enough to do any damage.


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