What to Use to Clean Your Freshwater Tank

What to Use to Clean Your Freshwater Tank in 2024

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Last Updated on March 31, 2024 by Jessica Lauren Vine

Wondering what to use to clean your freshwater tank?

It’s your rig, and for some of us, it’s our home.

They say you can go weeks without food but only days without water. That’s why having a clean and reliable freshwater tank is essential to long-stay RV folks.

Keeping your freshwater holding tank clean is critical not just to your health but to the enjoyment of your stay. Stinky and dirty drinking water can ruin everything about your RV experience.

RV freshwater tanks are essentially above-ground cisterns and, if left un-serviced, can develop bacterial growth that can make you sick.

I know this firsthand. Our family cabin in Northern Colorado was serviced by a 1000-gallon cistern which we failed to drain and clean for several years—not because of ignorance but circumstance.

We went up and planned on some hiking and fishing, but after drinking the water, everyone got sick. The simple pointers can keep you not just healthy but also improve your RV experience.

What Can Happen If You Don’t Clean Your Freshwater Tank

Let’s say you parked your rig last winter, and maybe it’s a little older model.

It’s been a busy year or two, and you have not had an opportunity to take it out or perform annual maintenance. The water in that tank has probably taken on some unwanted bacteria. That means the water is smelly and unpleasant to drink.

You are at the “Do not drink this water” phase of your RV experience.

There are a few simple steps you can accomplish to remedy this situation.

This solution is to drain your tank and then sterilize it before your trip to Yellowstone or the Black Hills. Your experience will be better after about an hour of work.


Start with the water heater.

It’s usually located on the outside of the backside of the RV. If you need to, refer to your owner’s manual.

There will be a spigot-looking thing with a relief valve.

Drain the water heater.

There are two red and blue relief valves under your rig connected to the freshwater supply.

You can drain the tank with these, but if you are unable to perform this task, you can open all faucets and the showerhead and activate the water pump.

Once the faucets are spitting out water and air, the tank is essentially empty.

This will also ensure that you have cleaned out your pump and waterlines from the stinky water. You can check your control panel to make sure it’s reporting that the tank is dry. Do not run your pump for long after the water is pumped out—IT WILL BURN UP.


Grab a bucket.

Mix chlorine bleach (which kills the bacteria in your tank) with water.

Do not pour unmixed chlorine bleach directly into your rig. It will be problematic.

You will need a portable hand water pump to get the bleached water from the bucket into the tank.

That’s why I love Harbor Freight tools. Once the concoction is in the tank with fresh water. Fill the tank. Run the water pump to get your lines and pump treated. If you’re not planning on taking your rig out, let it sit for a day so the chlorine can do its job. See how easy that was.

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03/30/2024 02:59 am GMT


Drain the tank (you can do it anywhere, chlorine is safe, you swim in it) and let it sit for another day empty. Fill with clean, fresh water. You won’t be sorry, and your RVing experience will be a lot better. Now get out there and enjoy life.

Now that you’ve learned what to use to clean your freshwater tank.

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