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Knowing how often to sanitize your RV water tank can be confusing, especially if summer is approaching and you need to get the RV ready for a trip.

Perhaps you left water in the tank from your last excursion, or your tanks are completely dry. Now, what do you do? If you sanitized the tank before your last trip, is it still good, or should you not take the chance?

The RV water tank should be sanitized every four to six months before each trip. The sanitization process should be the same for dry tanks and tanks that were recently used. If the water becomes stagnant, the process may be more complex in eliminating mold and algae buildup.

Thorough knowledge of how to sanitize your RV water tank from water-borne diseases and other risks that may develop from wintered water tanks can save you a lot of money and stress and prevent you or your family members from becoming ill.

If your RV water tank is even the slightest bit dirty or your sanitation regime is done half-heartedly, chances are high that you'll leave some contamination behind. Any remaining bacteria can multiply and spread through the entire RV watering system.



How Would You Know Your RV Water Tank Needs Sanitization?

Depending on when you use your RV and how long it stands between trips will indicate how often you should sanitize the water tank. If your RV is wintered, you should sanitize the water tank before doing anything else.

After standing for weeks or several months, any water in the RV tank will be stagnant, have a bad odor, and can be full of bacteria, black mold, or green algae. It is not a good idea to attempt to drink the water and avoid skin contact.

Tests you can do to verify sanitation is warranted –

  • Open the RV water tank cap and wave the smell towards your nose – never put your nose directly into a tank, container or bottle. Fumes can overwhelm you, and you can pass out.
  • Place a bucket underneath the drainage pipe, open the valve and let some water out into the bucket. Inspect the water for color, odor, or debris.
  • Switch on the water pump, open the taps and shower head inside the RV, and inspect it for debris, odor, and color.

Once you have established the need for sanitizing the RV water tank, you need to get the correct supplies and sanitizer. This will have to be done no less than 72 hours before departure.

The sanitizer should run through the system after standing for the required hours, whereafter the water tank and pipes should be flushed.

What Is The Correct Way To Sanitize Your RV Water Tank?

The sanitizing of the RV water tank is fairly simple, but it's not going to be effective if you pour large amounts of cleaner down the hatch and hope for the best. A more calculated approach is best.

Depending on the cleaner or sanitizer you plan to use, you will first gather all the necessary tools. They may include but not be limited to the following items –

  • The sanitizer or cleaning products
  • A bucket for mixing
  • A jug for scooping and pouring
  • A funnel
  • An external water pump
  • A hose to attach to the pump
  • Gloves
  • Respirator
  • Protective eyewear

You should wear the appropriate PPE or personal protective equipment when working with chemicals.

After collecting all the equipment, mix the recommended dosage of 1 cup of chlorine bleach with 50 gallons of water. This mixture will keep at 50ppm -  well below the safety threshold of 200ppm or parts per million.

If your RV water tank is 50 gallons, fill it halfway, pre-mix the cup of bleach with some water, pour it into the tank using the funnel, and fill it to the top. If the tank is bigger or smaller, here is what to do –

Using the bucket, make your bleach pre-mix in it and fill up the water tank of the RV. If the RV water tank is smaller than 50 gallons, a ¾ cup will be sufficient. If the tank holds more than 50 gallons, you can use a cup and a half, but no more.

Position the funnel into the opening of the RV water tank and pour the solution into the funnel using a jug.

Wear your PPE while working with the bleach, as direct skin contact can cause irritation and redness. Wear safety glasses to avoid accidental eye contact with the bleach solution at all costs.

Fill up the RV water tank to the maximum by using the hosepipe. As soon as the water starts spilling out, close the cap on the tank.

Switch on the water pump and go inside the RV. Open all the faucets fully and run the water. Open the shower head until you can smell the bleach water. If your toilet is connected to the system, flush it a few times.

Close all the faucets and the shower and exit the RV. Switch off the water pump and let the bleach water remain inside the pipes for nothing less than 12 hours but no more than a day as the bleach is caustic and can cause damage to some pipes.

After 12 hours, completely drain the system and fill the tank with fresh water. Switch on the water tank again. Open all the faucets and the shower and run the water until the bleach smell has disappeared. You may need to run it for several minutes.

Fill your RV water tank with good quality drinking water, ready for the trip.

Can You Only Use Bleach To Sanitize The RV Water Tank?

Other alternatives are available if you are more conscious of the environment and don't want to use chlorine bleach as a sanitizer.

In the past, finding a solution that could kill germs and bacteria as effectively as bleach and not harm people, animals, or the environment was challenging.

Today it is much easier to find a solution that will not leave residue in the water, kill bacteria and be safe to consume.

Environmentally Friendly Sanitizer Alternatives

The following alternatives can be used instead of chlorine bleach –

The high acidity in white spirit vinegar and its ability to kill and neutralize bacteria is well documented. If you decide to use white spirit vinegar, you must use heated water.

Vinegar is more effective when the water is at least 130 degrees F. Three to four cups per 50 gallons is effective.

If you are in the middle of nowhere and you come across less than desirable water for the tank, and rock salt is all you can find, it will work well to sanitize the tank and pipes. You will need to heat the water so the salt can dissolve.

Driving around may help shake things up a little. Three cups per 50 gallons should be sufficient.

One of the best alternatives is hydrogen peroxide, with 30% or 40% volume. When undiluted, hydrogen peroxide can be volatile, so never shake the container before opening it. It may pop open violently, and the higher volumes of peroxide can burn the skin.

Similarly, with vinegar and rock salt, you will need to heat the water to 130 degrees F and push the solution through by opening all the taps.

Hydrogen peroxide kills bacteria by causing oxidation of the cell walls and neutralizing them.

What Are The Benefits Of Using Hydrogen Peroxide Regularly?

Because hydrogen peroxide is so versatile, safe, and fast-acting against most pathogens, it has more benefits as an RV water tank sanitizer and can therefore be used more often to keep the tank hygienic.

The following benefits of hydrogen peroxide as an RV water tank sanitizer are well documented and used by the military in a formula stabilized with colloidal silver –

  • You will not have an aftertaste in the water
  • It will not alter the water pH
  • It contains no pollutants or added ingredients
  • It is completely odorless once mixed with water
  • Effective against algae, bacteria, microorganisms, mold, and other water-borne pathogens.
  • It is environmentally friendly and will not affect sewage systems
  • It is chlorine-free
  • It removes any buildup and bio-films on the inside of pipes.

The Risks Of Regularly Sanitizing The RV Water Tank With Bleach

Chlorine bleach is a strong-smelling chemical and is fine to use occasionally. However, if you regularly use chlorine bleach to sanitize your RV water tank, you may start to notice the bleach smell stays in the water.

That can be because it breaks down the plastic pipes and penetrate them. The bleach can take several days to be fully eliminated from the water tank.