Sanitizing Fresh Water System

Here’s the easy process to get your fresh water holding tanks so clean you can drink out of them.

Frequency

If you use your freshwater holding tank at all, you need to sanitize it. How often? At least twice a year, no matter how often you use your RV. If you are a full-timer or use your RV and it’s freshwater holding tank pretty frequently, then plan on sanitizing that tank three to four times a year, at a minimum.

Ingredients

To sanitize the water system in your RV, use a quarter cup (two ounces) of household bleach for every fifteen (15) gallons of water your freshwater tank holds. Since our freshwater tank is 52 gallons, we need 7 oz or about a full cup of bleach.

Process

  1. Turn off water heater! Drain any freshwater you currently have in the freshwater tank.
  2. Add bleach to the freshwater system. A technique is to add it to the freshwater hose prior to connecting it to a water source.
  3. Fill the freshwater tank with bleach/water.
  4. Run water through everything: kitchen, bathroom, shower, toilet.
  5. Leave the mixture in contact with the tank and all water lines for a minimum of 4 hours (overnight is best).
  6. Run all taps again putting water in black/grey tanks.
  7. Fill freshwater tank again with potable water and flush pipes again to remove remaining bleach.
  8. Fill freshwater tank gain with potable water and let stand for an hour, then flush again.

Notes

  1. Do not use “splash-less bleach.” The active ingredient, sodium hypochlorite, only has a 1-5% concentration, not enough to sanitize and disinfect, as the label on the bottle will warn. Use regular, household bleach instead.
  2. Household bleach can be extremely corrosive. It’s important to wipe down any surfaces that it may have spilled on with water or ethanol and definitely avoid letting bleach stay in contact with delicate metal instruments or structures (such as your holding tank’s sensor probes) for very long.
  3. Bleach can also damage rubber or plastic parts and surfaces, such as water supply and waste disposal plumbing pipes, holding tank seals, and other soft, delicate parts in your RV.