How to Drain an RV Fresh Water Tank

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The best thing about RV travel is the freedom of mobility that it provides. It’s a home on wheels, and part of what makes it that is the ability to hold its own water supply. That’s where the fresh water tank comes in. If you’re camped at a location with very limited hookups, you can use your tank as an alternative. If you are using your fresh water tank then you clearly know how to fill it up. Simply using the water in your rig until the tank is empty might seem very easy, but this won’t be able to empty out all of the water from your tank.

So, how do you drain your RV’s fresh water tank?

Draining your fresh water tank is very simple. All you have to do is locate the drain valve underneath your RV and open it to release the tank’s contents. Be sure to do so slowly to avoid making a huge mess.

The important part is less about the actual draining of the tank, but making sure you properly prepare for it. Let’s take a closer look at how you can do this.

What to do Before Draining The Fresh Water Tank?

There are a few things you’ll want to do before emptying your fresh water tank. One of the most important first steps is making sure both your water heater and water pump are turned off. Make sure you give some time for the water to cool down if you just recently used your heater. Once that’s done, you’ll then want to run all the faucets and your shower head at the same time.

While leaving the faucets and shower to run should in theory empty everything, this is not the case. It is an important step for removing the bulk of the water before emptying, but there will always be some leftover in the tank. That’s where the draining process comes in.

First, you’ll need to find the drain valve underneath your RV. Your fresh water tank is also located underneath your rig and as such the drain valve is typically very close by. However, if you can’t find it, your RV’s owner’s manual will help you. If you no longer have the manual, there is always an online version that you can find specific to your rig.

Once you’ve located your drain valve, you also need to find the low-point drain valves. These are usually right beside the normal drain valve so you can’t miss it.

But what are the low-point drain valves?

Your rig’s two low-point drain valves are for emptying hot and cold water respectively from your water lines. Opening both the drain valve and low-point valves are crucial in removing excess water from both your tanks and pipes. Now that you know what steps to take and what to look for before draining, let’s move onto emptying your fresh water tank.

Emptying The Fresh Water Tank

Out of all your holding tanks, the Fresh is usually the easiest to drain. When emptying your black or grey tanks, you must hook your rig up to a sewer or a portable tank so as to dispose of all the waste. Since your fresh water tank does not contain any waste, there are no rules and regulation for where or how you must drain it. You could even do so right at your campsite! Now, it’s important to exercise common sense when emptying your tank, be considerate of the environment, people and other vehicles/rigs around you. Beyond that however, you’re good to go

Additionally, there is no need for you to connect a hose to any of the fresh water tank valves like you would for the waste tanks. You can just release the valve and let the water flow out. However, it is advised to slowly open the valve just to prevent water from rushing out very fast. It’s not dangerous, just very messy. The reason you run your faucets and shower beforehand is because the fresh water tank can hold anywhere from 20-80 gallons depending on the make, class and size of your rig. No one wants that much water rushing out at them so allowing the bulk of it to be used by your amenities makes the whole process easier.

Since the fresh water tank can hold so much water, it begs the question, can I leave water in the tank?

Can Water Be Left In The Fresh Water Tank?

Generally, the maximum amount of time you’ll want to leave water in the tank is about 2 weeks. This is only if you are not driving your rig. Never drive with a lot of water in your fresh water tanks, or any tanks for that matter. All this will do is weigh down your RV, which taxes the engine and forces your rig to use more fuel.

If you are not driving, don’t exceed the 2 week limit as any longer just promotes stagnant water. Mold, bacteria and even algae can grow in the tanks. All of which can cause a persistent bad smell in your RV. You definitely don’t want to be washing up or cooking with water that’s not fresh.

When storing your RV, definitely make sure the tanks are empty. This is especially important for winter storage, as water sitting in your rig can end up freezing and causing damage. The general rule of thumb to follow is, if you are not going to be immediately using the water, don’t leave it in your tank. Luckily, if you’ve made the mistake of leaving water in your tanks, the cleaning process is very simple.

How to Clean The Fresh Water Tank

Out of all your holding tanks, the fresh water tank is the most important to keep clean. Once you’ve successfully emptied the tank, you’ll want to flush it out with a mixture of bleach and water. To figure out how much bleach to use, simply use one ounce for every 8 gallons of water. Fill your tank around halfway with this mixture, and then the remaining half with water. Let this sit in your tank for around 10-12 hours and then drain it as you normally would. You can also run your faucets while this mixture sits in your tank if you want to clean your pipes as well. Either way, flushing your tank with just a little bit of bleach can go a long way in keeping it clean and your water fresh.

Closing Thoughts

Your fresh water tank makes those remote trips way easier. Knowing when to keep water in it and how to drain it will keep both your rig and the tank in its best shape. Emptying the grey and black tanks are easy enough, but your fresh water tank is even easier to manage. As long as you remember to prepare beforehand and drain it slowly and often, you will keep your fresh water tank as clean as it can be!