How To Sanitize an RV Fresh Water Tank

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RVs have holding tanks that allow campers to travel with fresh water. However, to ensure you have safe water to drink, wash dishes and bathe, your RV fresh water tank needs to be cleaned regularly. Below is a step by step guide on how to sanitize an RV fresh water tank.

For more step-by-step RV maintenance guides, check out our eBook: The Owner’s Guide to RV Maintenance.

When to Sanitize an RV Fresh Water Tank

If you are wondering, how often should you sanitize an RV fresh water tank, it depends on how you use your RV. Always clean your RV fresh water tank at the following times:

  • On new RVs before your first trip
  • Before long periods of storage 
  • After not being used for a period of time
  • After contamination (i.e. Being filled with water in Mexico)
How to Sanitize an RV Fresh Water Tank
Always sanitize an RV fresh water tank before your first trip

How to Sanitize an RV Fresh Water Tank

Tools Required

Sanitizing an RV fresh water tank is a pretty simple process, but there are a few supplies you will need to have on hand. Have a These includes:

  • 5 gallon bucket
  • A garden hose
  • Household bleach
Only basic tools are needed to sanitize an RV fresh water tank
Only basic tools are needed to sanitize an RV fresh water tank

Step One: Empty Tank

First, turn off your RV’s water heater as it should never be on with an empty tank. Then, empty the fresh water tank. You can empty the fresh water tank using the fresh water drain valve on the bottom of the RV. See our complete guide to draining fresh water RV tanks for more details.

Step 2: Mix Cleaning Solution

The cleaning solution is made by mixing bleach and potable water.  Mix ¼ cup of bleach and 1 gallon of water for every 15 gallons of tank capacity. If your fresh water tank holds 45 gallons of water, your solution will be ¾ cups bleach and 3 gallons water. The bleach is what will kill germs and sanitize the fresh water tank.

Step 3: Bypass Hot Water Heater

To prevent bleach from entering the water heater, turn on the water heater bypass. The water heater bypass valve is usually located on the control board (see picture in next step) or on behind the actual water heater. Check your owner’s manual for the exact location.

Step 4: Put Cleaning Solution into the Tank

If your RV has a control board like the one pictured below, turn knobs to the sanitize setting. Hook up a garden hose to the fresh water inlet and place other end of hose in the bucket of cleaning solution. Turn on the water pump and your solution should be suctioned from the bucket into the tank.

RV water panel
Sanitizing an RV Fresh Water Tank Using the Control Board

If your RV does not have an automatic sanitize setting, you can use a funnel to pour the cleaning solution directly into the garden hose before hooking the hose up to your water source.

Step 5: Fill Fresh Water Tank

Completely fill the rest of your fresh water tank with potable water.  After filling the tank with water, turn on all faucets in the kitchen and bathroom and run water until you smell bleach.  This will ensure that all fresh water lines are sanitized.

Step 6: Wait

Let the cleaning solution sit in the tank a minimum of four hours. Letting the solution sit for eight hours is ideal. Sanitizing tanks before bed and allowing the solution to sit overnight is a good option for RVers who want to sanitize the fresh water tank while camping.

Step 7: Drain and Flush the Tank

Completely drain the fresh water tank. Then, completely refill and drain again.  Repeat this process until you no longer smell bleach. It will usually take three to four rounds of flushing.

Draining RV Fresh Water Lines
Enjoy fresh water after sanitizing your RV fresh water tank

Tips for Clean RV Drinking Water

Sanitizing your RV’s fresh water tank is essential if you want to drink water out of your RV faucets. However, there are other steps to take to ensure you always have clean drinking water on the road.

Ask the Locals

When making a reservation at an RV park or campground, ask the person working the phone about the quality of the drinking water. Campground workers should be aware of any quality issues with their water system and can let you know if the water is safe to drink or if it tastes a bit funky.

If the campground indicates that they have a water quality issue, you can fill your tanks with potable water before arriving. If you fill your fresh water tank with water that is not recommending for drinking, follow the above steps and sanitize your RV fresh water tank before drinking water from the faucet.

Use a Water Filter

Sanitizing an RV fresh water tank ensures that clean water is not contaminated by your tank. However, a water filter helps clean the water coming into your RV. A water filtration system is a good idea for any RVer who plans to use water from their tanks for cooking and drinking.

Berkey Water Filter

Berkey Water Filter

Berkey water purification systems are the ultimate water cleaning system for RVers. The Berkey is the same system used by the Red Cross when going into areas with non-drinkable water. As the Berkey is a gravity-fed system, it does not require water pressure or electricity to function. The downside of the Berkey filters, is the price. Starting at over $300 for a travel-size filtering system, Berkey’s are effective but not cheap.

Camco Water Filter

Camco RV water filter
Camco Water Filter

If a Berkey is out of your price range, there are other water filter systems to consider. The Camco EVO water filter attaches between the garden hose and your fresh water inlet to filter all the water coming into the RV. The filter reduces bad taste, odors, sediments, bacteria, chlorine and more from the water supply. See our review of the best RV water filters for more options.

Purchase Responsibility

When camping at a location where potable water is unavailable, look for responsible ways to access clean drinking water. Instead of buying single-use plastic bottles, keep water jugs on hand and refill them at local water refill stations. Use this link to find water refill stations near your campsite.


Now you should have clean drinking water !

We have several more maintenance guides to help you prevent issues with your RV appliances and components.

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