Sanitizing Your Fresh Water System

 

A motorhome's fresh water tank is only fresh as long as it stays clean. Over time "things" tend to grow in humid environments so it's not always the best idea to store your drinking water in a dirty container with all sorts of bacterial growth. Fortunately, there are means to sanitize the system to kill any bacteria that may be hiding in the tank, lines, or fixtures. This is done by adding chlorine bleach to the system, running it through the plumbing, then allowing it to sit, before flushing it out with clean water. The following tips should help you to sanitize your fresh water system.

Many people don't understand the difference between pressure and flow, but you need to in order to solve your problem. "Flow" is a measure of volume of water delivered in a period of time. The poor shower is caused by low flow, as are most other RV water supply problems. "Pressure" is a measure of the force of the water, and it is measured when no water is flowing ("static" pressure). It is true that for a given plumbing system, the higher the pressure, the better the flow. However, there is a practical limit to increasing pressure to improve flow.

 

Purifying by adding liquid chlorine bleach

If boiling is not possible, water can be made safe for drinking by treating with liquid household chlorine bleach, such as Clorox, Purex, etc. Household bleach is typically between 5 percent and 6 percent chlorine. Avoid using bleaches that contain perfumes, dyes, and other additives. Be sure to read the label.

Place the water (filtered, if necessary) in a clean container. Add the amount of bleach according to the table below. Mix thoroughly and allow to stand for at least 30 minutes before using (60 minutes if the water is cloudy or very cold).

Purifying tablets or chemicals designed for use when camping or backpacking can also be an effective way to treat water. Always follow the directions on the package.

Treating Water with a 5-6 Percent Liquid Chlorine Bleach Solution
Volume of Water to be Treated Treating Clear Water: Bleach Solution to Add Treating Cloudy, Very Cold, or Surface Water: Bleach Solution to Add
1/2 gallon/2 quarts/2 liters 3 drops 5 drops
1 quart/1 liter 5 drops 10 drops
1 gallon 10 drops or 1/8 teaspoon 20 drops or 1/4 teaspoon
5 gallons 50 drops or 2.5 milliliters or 1/2 teaspoon 5 milliliters or 1 teaspoon
10 gallons 5 milliliters or 1 teaspoon 10 milliliters or 2 teaspoons

 

Sanitizing your RV System

It is recommended that a chlorine solution of one gallon of water and cup of chlorine bleach (Clorox) (5% sodium-hypochlorite solution) be prepared for every 15 gallons of fresh water tank capacity.

To sanitize your water system in your RV will require the following solution:

1. Drain the fresh water tank by opening the drain valves. There is one valve for each water tank. All of the faucets on the RV should be in the closed or off position.

2. Prepare a chlorine solution of (5% sodium – hypochlorite solution. (See above table)

For sanitizing purposes a -

1 gal. of solution ( water plus cup bleach) would treat a 15 gal. water tank

2 gal. of solution (water plus 1 cup bleach) would treat a 30 gal. water tank

3 gal. of solution (water plus 1 cup bleach) would treat a 45 gal. water tank

4 gal. of solution (water plus 2 cups bleach) would treat a 60 gal. water tank

5 gal. of solution (water plus 2 cups bleach) would treat a 75 gal. water tank

6 gal. of solution (water plus 3 cups bleach) would treat a 90 gal. water tank

7 gal. of solution (water plus 3 cups bleach) would treat a 105 gal. water tank

 

Disinfecting Your Fresh Water System After Long Periods of Storage:

Prepare a chlorine solution using 1 gallon of water and 1/2 cup of chlorine bleach ( 5% sodium-hypochloric solution). Prepare enough of the chlorine solution to administer one gallon of solution for every 15 gallon of fresh water tank capacity. This mixture puts a 50 PPM (Parts Per Million) residual chlorine concentration in the water system that will act as a quick-kill dosage for harmful bacteria, viruses, and slime-forming organisms. Concentrations greater than 50 PPM may damage the water lines and/or the tank.

Pump the chlorine solution into the tank by first placing the winterizing hose into the chlorine solution. Close the valve from the fresh water tank to the pump and open the valve from the solution to the pump. Turn the tank fill valve from the "city water" to "tank fill". Turn on the water pump until all the solution is pumped into the fresh water tank.

Turn off the water pump. Then close the valve solution. Open the valve from the tank to the water pump. Fill the water tank with the city water fill ( or by using the same method as was used to put the sanitizing solution into the tank). Remove the water filter (located in the sanitation compartment outside the motor home) and install the by-pass pipe to allow the sanitizing solution access to the faucet. Open each faucet, in turn, including the kitchen faucet, bath faucet, inside and outside showers, turning "on" both the hot and cold faucets, and flushing the toilet until all of the air has been purged from the pipes and the water runs freely. The entire system will then be filled with the sanitizing solution.

Allow the 50 PPM disinfection solution to stand in the system at least 4 hours.

Drain the system and flush it with fresh water. The water system needs to be flushed with water repeatedly, if necessary, until there is no chlorine taste or smell left in the system. To remove any excessive chlorine taste or odor that might remain, prepare a solution of one quart vinegar to five gallons of water. "Rock" the tank containing the solution by moving the motor home forward and backward several times to clean the tank, then drain that tank and re-fill with water.

 

Submitted by Mike Sundberg - 3/15/06