Sanitizing Hot and Cold Fresh Water Tanks

Key to maintain comfort on your RV-adventures is to keep all holding tanks sanitized and clean, see how to do it….

Sanitizing hot and cold fresh water tanks

What you need

  1. Pourable container such as a gallon jug
  2. Common household bleach
  3. Measuring cup


  1. Ensure that your fresh water tank is about half full so there is enough room to fill it with water after adding bleach
  2. Turn off ice maker and water dispenser on your kitchen sink (if you have any in your RV) before sanitizing
  3. Take the water heater offline so no bleach enters into the water heater
  4. Mix ¼ cups of household bleach with about ¾ gallon of water in your gallon jug. You want to have ¼ of bleach for every 15 gallons of tank capacity
  5. Turn on your fresh water tank fill then place the plastic winterizing intake pipe into your bleach solution
  6. Turn on the water pump  and the intake pipe will draw the bleach solution into the fresh water tank
  7. Rinse the winterizing intake pipe by drawing a gallon of non-bleach fresh water into the water tank
  8. Fill up the water tank with fresh water until it spills from the overflow tube
  9. Once the tank is full of bleach solution water, run all the cold and hot water faucets until you smell bleach to sanitize them as well
  10. Leave the sanitizing solution to sit inside tank four at least 4 hours to 8 hours so it has time to disinfect
  11. It is advised to drive your RV part of that time so the water inside the tank is agitated for maximum disinfection
  12. Once the time is up, drain your water tank and refill with clean water. Run the water through hot and cold faucets until you no longer smell the bleach

Most bleaches are based on solution of chlorine

How to Properly Empty RV Holding Tanks

  1. Use Thetford Aqua Kem or rapid dissolve tissue to avoid tissue build up in the RV pipes
  2. Use tissue digester products to prevent or eliminate clogging
  3. Wait until the black water tank is about ¾ full before trying to drain it
  4. Always empty the black water tank first and close the black water valve to avoid contamination of your grey water tank system
  5. Empty the grey water tank to clean the drains and hose

Disinfecting Gray and Black Water Tanks Chemicals:

Camco 41172 Orange TST Holding Tank Chemical Packs

  • Controls odors
  • Breaks down waste and tissue fast
  • Cleans drain lines and tank walls effectively


  • 2 oz. of product is needed for every 40 gallons of tank capacity
  • This chemical should not be mixed with other toilet chemicals. 
  • To clean first drain the RV system and flush black or grey water tank before using

Thetford Aqua-Kem Blue

  • 100% biodegradable
  • Proven use for over 50 years
  • Liquefies waste and tissue quickly
  • Odor fighting formulation


  • Use the proportion of 120ml for every 20 gallons of tank capacity 
  • Add to toilet or directly into black or grey water tank then add up to 3 liters of water

Steps to rinsing and flushing out black water tanks

  1. Empty and drain the black water tank system prior to rinsing and flushing
  2. Use a tank cleaning wand or flush valve to thoroughly clean the water tank
  3. The flush valve and cleaning wand both shoots out powerful jets of water back into the holding tank in order rinse out any clogged areas
  4. The wand can be used directly into the toilet bowl for the same effect of jetting water into the holding tanks
  5. The wand has flexible models that are also capable of being used in drain lines and can spray in any direction

Steps to rinsing and flushing out grey water tanks

  1. First prevent food and greasy grime from entering your RV plumbing because it collects and causes odors
  2. Empty the grey water tank then add an approved grey water treatment down the sink drains to prevent odor accumulation and clean the tank
  3. Pour some dish-washing liquid down the sink and shower drains followed by some water in order to break down the grease that accumulates in grey water drains
  4. Replace traditional P-traps with a HepvO one which enables water to go through it into the holding tank but no gases or odor to pass back from the tank

Top of the Page


 About Us / Privacy Policy / Resources

Go to:  Pop-up Travel Trailers and RVs