To sanitize an RV fresh water tank, drain the old water, then add a mix of clean water and regular unscented bleach. A common amount is 1/4 cup of bleach for every 15 gallons of tank size. Fill the tank, run the water through each faucet until you smell a light bleach scent, then let it sit for several hours or overnight. After that, drain the tank and flush it with fresh water until the bleach smell is gone.
Now let’s go through the full step-by-step process.
If your RV has been sitting for a while, your fresh water tank should be cleaned before you use it. Even if the water looks clear, the tank and water lines can still have old water, smells, or buildup inside.
Your RV fresh water tank holds the water you use for sinks, showers, and sometimes drinking. Over time, the tank can pick up smells, bad taste, or bacteria, especially if the RV has been stored.
You should sanitize your RV fresh water tank:
For RV owners in Minnesota, this is a smart spring checklist item after a long winter.
You do not need much to clean your RV fresh water system.
Do not use scented bleach. Do not use splash-less bleach. Do not mix bleach with any other cleaner.
Use 1/4 cup of bleach for every 15 gallons of fresh water tank size.
Before you start, check your RV owner’s manual. Some RVs may have special instructions, especially if they have water filters, tankless water heaters, or special plumbing.
Start by draining the fresh water tank. Open the drain valve and let the old water run out.
You should also drain the water heater if your RV has one and the manual says it is safe to do so. Make sure the water heater is turned off first. Never drain a hot water heater while it is hot or under pressure.
Do not pour straight bleach directly into the tank.
Instead, mix the bleach with water first. You can mix it in a clean container or pour it into the hose before filling the tank, depending on your RV setup.
This helps spread the bleach through the tank more evenly.
After adding the bleach mix, fill the fresh water tank with clean water.
Once the tank is full, turn on the water pump.
Go inside the RV and open each faucet one at a time.
Run the cold water until you smell a light bleach smell. Then do the same with the hot water side, unless your RV manual says to bypass the water heater.
The goal is to get the bleach water into all the water lines, not just the tank.
Let the bleach water sit in the system for several hours. Many RV owners let it sit overnight.
Try not to use the water during this time.
This gives the bleach time to clean the tank and water lines.
Turn the pump back on and run clean water through every faucet.
Keep flushing until the bleach smell is gone. You may need to fill and drain the tank more than once.
Take your time with this step. You do not want your first camping trip of the season to come with bleach-smelling water.
Here are a few simple tips to make the job easier:
If your RV has been winterized, make sure the antifreeze is flushed out before using the fresh water system.
Many RV owners do drink water from their fresh water tank, but only when the tank, hose, and water source are clean.
If you plan to drink from your RV tank, sanitize it often and use a drinking-water-safe hose. Some people also add an RV water filter for better taste.
If you are unsure about the tank’s condition, use bottled water for drinking and cooking until the system has been checked.
A good rule is to sanitize the tank at least once a year.
You may want to do it more often if:
Sanitizing your RV fresh water tank is a job many owners can do at home. But if your water pump is not working, your faucets have low pressure, your tank smells bad, or you see leaks, it may be time to have it checked.