How To Fill Your RV’s Freshwater Tank (In 4 Steps)

When you are new to RVing, there are so many new things to learn. One of the most important is filling your RV water tank with fresh water.

Your freshwater tank allows you to have clean water for drinking, showering, and washing dishes, even when you’re not close to a water source.

Filling your freshwater tank is actually a simple process. It only takes a few easy steps and your tank is ready to travel. In this article, we’ll provide step-by-step instructions on how to fill your RV’s fresh water tank.

filling rv water tank with fresh water

Filling RV Water Tank With Fresh Water: Step-By-Step

There are times when you are on the road that you may not be able to connect to a freshwater source. Or if you like to take your RV or travel trailer out to more remote locations, you’ll need to make sure that you have a reliable source of water. 

Your RVs freshwater tank is made for these types of situations, allowing you to have a safe source of water even when you’re not near a water supply.

Filling your RVs freshwater tank is a simple process. There may be a bit of slight variation to this process, depending on your RV. However, the steps we will detail below are fairly universal and will work for most RVs. 

We do recommend that you also consult your RV’s owner’s manual for specific details for filling your RVs freshwater tank.

1. Familiarize Yourself With Your RV’s Water System

This is a really important step in making sure you know how to utilize your RVs water system. Most RVs and travel trailers have three separate tanks for different types of water. 

The purpose of the water system in your RV is to deliver fresh water and store used water. Most RVs will have two or three tanks in the water system, and each has its own maintenance needs.

  • The Freshwater Tank – This one is sort of self-explanatory. This is the tank that holds the water that you’ll use for drinking, cooking, and showering. Your RV’s toilet also fills from this tank.
  • The Gray Water Tank – Gray water is water that is used but does not contain human waste. The gray water tank holds used water from the shower and sink of your RV.
  • The Black Water Tank – The black water tank is where the waste and water from your toilet goes. Some RVs don’t have a gray water tank. In this case, the used water from the shower, sink and toilet will also go to the black water tank.

2. Locate The Intake Valves On Your RV

Now that you know a bit about your RVs water system, you’re ready to locate the intake valves on your RV. These valves are how you get fresh water into your RV.

There are two typical configurations for RV and travel trailer freshwater intake valves.

  • The first configuration is that your RV has two separate intake valves. One for “city supply” and one for “local supply”. The “local supply” intake valve fills your RV’s freshwater tank.
  • The other configuration is a single intake valve that has a lever or switch that sends water to the freshwater tank in one position, or to the RV’s plumbing if you’re connected to a water supply.

3. Connect The Hose

Now that you’ve located the intake valves on your RV, it’s time to connect the hose. This is simple. Attach one end of the hose to the intake valve, and the other end of the hose is connected to the water spigot.

You’ll want to invest in a hose that is used only for filling your freshwater tank or connecting to city supply. Usually, freshwater hoses are white, but sometimes they’re blue. 

4. Fill The Tank

With your hose connected, you can now turn on the water and fill your RV’s freshwater tank.

Make sure that you keep an eye on the fill level, so you don’t overfill.

How To Clean An RV Freshwater Tank

Even though you fill your freshwater tank with potable water, that doesn’t mean that it is unable to grow algae or bacteria over time.

The easiest way to keep this from happening is to clean and sanitize your RV’s freshwater tank. 

Here are the steps necessary for cleaning the freshwater tank in your RV.

The first thing you need to do to sanitize your freshwater tank is to turn off the water pump and water heater. Both features in your RV can be damaged if you drain them while they are on.

  • Drain the Freshwater Tank

After turning off the water pump and water heater you can now drain your freshwater tank and plumbing. To do this, you’ll need to locate the low-point drains underneath your RV. 

These drains will allow you to drain both the freshwater tank and the hot and cold plumbing lines. The drains open with a simple valve. Open the valve and let the water drain onto the ground. 

  • Add Bleach

Once the freshwater tank is empty, you’ll want to add some fresh water, so the tank is about half full. 

To a bucket or watering can, you’ll want to measure an appropriate amount of household bleach. The recommended amount of bleach is 1 cup per 50 gallons of water. If your freshwater tank is 15 gallons, you’ll want approximately 1/3 cup of bleach. 

Add water to the bleach in the bucket to mix. Pour the bleach-water mixture into the freshwater tank. You may want to use a funnel or a gravity tank filling attachment for easy transfer. 

When you’ve added all of the bleach-water mixture to the freshwater tank, fill the tank the rest of the way.

For some non-bleach options, see this article.

  • Pump Bleach Water Through the RV Plumbing

Turn on your water pump and pump the bleach-water mixture through the RV plumbing. Do not turn on the water heater. 

This will pull the bleach water into the water heater. Bleach when heated can become corrosive to the inside of the water heater and cause damage.

  • Let Sit

For the best results, you’ll want to let the bleach-water mixture sit in the freshwater tank and your RV’s plumbing for 12-hours. This will allow the bleach to kill any algae or bacteria in the tank or plumbing lines. 

This will also breakdown any funky odors that may have developed in the lines and freshwater tank.

  • Drain the Freshwater Tank

After letting the bleach-water sit in the plumbing and freshwater tank, you’ll then drain the tank and the plumbing. To do this, once again open the low-point drains and allow the water to run out of the RV onto the ground.

  • Rinse the RV Plumbing

When the freshwater tank is empty, close the drains and refill the tank with freshwater. Pump the water through the plumbing and allow the water to run into the gray water tank.

You’ll want to let the water run in your sinks and shower for a bit of time, to allow all of the bleach-water to pass through the system.

If you’ve rinsed the plumbing lines and still have water in the freshwater tank, you’ll want to drain it one last time to rinse it free of any remaining bleach-water.

  • Refill the Freshwater Tank

Now that your RV freshwater tank and plumbing are clean you can now refill the freshwater tank with clean water, and you’re ready to hit the road for your next great adventure.

How Often Should I Clean My Freshwater Tank?

A good rule of thumb to follow when it comes to cleaning your freshwater tank is to clean it once every six months.

This is a good way to keep algae and bacterial growth in check and reduce the potential for strange odors and flavors. 

We suggest that you also clean and sanitize your freshwater tank and plumbing every time you take your RV out of storage in the spring. This is especially important if you use winterizing chemicals in your RV’s plumbing. 


Can You Fill Your RV Water Tank At Gas Stations?

The answer to this question is – sometimes. Many gas stations have outdoor spigots that you can use to fill your RV’s freshwater tank.

Travel centers like Flying J, Loves, or Pilot often have a freshwater spigot that is available for filling your RV freshwater tank, and often you can do this for free.

Smaller gas stations may or may not allow you to fill your RV freshwater tank. The best thing to do is check with the attendant to see if they will let you fill your water tank.

Some will and do so without charging you. Some small gas stations will let you fill you’re your water tank at a nominal fee.

Even if you see a spigot on the outside of a gas station, make sure you ask first. It’s just a thoughtful thing to do. 

How Do You Know When Your RV Water Tank Is Full?

There are a couple of ways that you can tell when your RV water tank is full. Which you use depends on your RV or travel trailer.

First you can watch the water-level gauge. Some RVs have these near the water inlet. If your RV doesn’t have a water fill gauge, and you can see the freshwater tank, you can watch the level in the tank.

If none of those options work, you can always listen for the water to get near the opening of the inlet valve.

Most RVs have an overflow on the freshwater tank. If you aren’t paying attention, the water will spill out the overflow and onto the ground.

Where Can I Fill My RV Water Tank Near Me?

If you are on the road and need to fill your RV freshwater tank, there are some reliable spots where you can stop and get some clean, potable water.

  • Campgrounds/RV Parks – these are really your best bet. Campgrounds and RV parks have plenty of water spigots with potable water, so they are a good place to stop and fill your freshwater tank. Some campgrounds or RV parks will charge to fill your water tank, others will let you pull in and fill for free. You may want to call ahead before stopping at a campground or RV park just to make sure that they will let you fill your water tank. 
  • State, County, and City Parks – A lot of city and county parks, especially those with day use areas have access to fresh water. State parks with camping facilities are also a good spot to stop and check for freshwater. Most of these areas won’t charge you to fill up your freshwater tank. State Parks, however, may charge an entrance fee.
  • Rest Stops – In the era of Covid, this may not be as reliable a source, but it’s worth the try. Rest stops, if they are still open, often have freshwater spigots that you can tie into for a quick fill-up. Some rest stops even have dump stations that you can use to empty your black and/or gray water tanks.
  • RV Dealerships – This is another great option, especially if you’re pulling through a more urban area. RV dealerships often have fill stations, and some even have dump stations. Many RV dealerships offer these services for free. Camping World is one of the best RV dealerships for these services. Almost all Camping World locations have fill and dump stations, and some will even let you stay in their parking lots overnight for a small fee if you need.
Madeline Cooper