How to Drain a Reverse Osmosis Tank

In this article, we will review how to drain a Reverse Osmosis tank. This article is meant for people who have a reverse osmosis system installed on their house as well as those who are planning to install one.

In general, RO systems use salt or potassium permanganate as an oxidizer to create the necessary pressure for the water. The water passes through a membrane with pores that are too small for particles of table salt and other minerals to go through.

But what happens when your RO tank needs a good clean? Follow this guide and you’ll be able to do it yourself without any problem!

What You’ll Need

Depending on how dirty your RO membrane is, you will need different types of materials to clean the tank.

For a moderately dirty membrane, you’ll need:

  • A bucket or large bowl
  • Hydrogen peroxide (or another type of disinfectant)
  • A scrub brush
  • White vinegar (optional)

For a severely dirty membrane, you’ll need:

  • Mild household cleaner (in addition to the other items)

We recommend that you use white vinegar when cleaning your system. It’s easy and inexpensive. However, if you want to use something else like hydrogen peroxide or other disinfectants, go for it! Just make sure to follow all the manufacturer’s directions.


The first thing you should do is to turn off the water supply.

This is important because if you don’t, there’s a chance that the water could get in contact with the electrical system which could short circuit it.

It’s also important to make sure there’s no pressure in the system. This can be done by opening any faucets on the property and letting the pressure out.

Next, you’ll need to drain any remaining water in the RO tank. You can do this by opening the faucet at the bottom of your tank (which will open when you remove all pressure).

Drain the Tank

First, you will need to get the water out of the tank. To do this, shut off the water supply valve to the RO system. Next, open up the drain valve at the bottom of the tank to allow all of the water to drain down into a bucket or container below.

To make sure that all of the water is drained from your tank, you can either unscrew and remove the lower pipe from your faucet or open up another drain valve. Ideally, if you have enough space in your lower storage area then it would be best not to use your faucet.

Next, check for any standing water inside your tank so you know when it has been completely drained. Remove any excess debris from inside your tank with a vacuum cleaner brush attachment if needed.

Here are step-by-step instructions:

  1. Make sure the tank is empty.
  2. Place a bucket or other container at the base of the tank.
  3. Remove the drain plug and allow the water to empty into the container.
  4. Remove any remaining water, using a hose if necessary.
  5. Clean the tank with hot water and vinegar or baking soda, rinse, and refill with water.
  6. Replace the plug and refill the tank with water.
  7. Repeat this process every two weeks or more often if your household consumes a lot of water or uses hard water (such as well water).

Cleaning and Refilling the Tank

First, you will need to clean the membranes by rinsing them in a solution of water and bleach. After that, rinse them again with potable water.

Next, refill your tank with fresh water and add new salt or potassium permanganate pellets.

Finally, close the valves of the RO tank and let it run for about 20 minutes to ensure that it is fully cleaned.

Does a Reverse Osmosis System Need a Drain?

As mentioned before, RO systems use salt or potassium permanganate as an oxidizer to create the necessary pressure for water to pass through the membrane. This is why it’s important to make sure you drain your tank periodically.

Reverse osmosis systems are all similar in this way, so if you’ve installed a RO system on your house, you know how to clean it!

It’s advised that you drain the contents of your tank at least once per year. If you don’t do this, you risk losing up to 50% of your water pressure due to mineral buildup.

The easiest way is to attach a garden hose and then open the spigot that’s on the bottom of your tank until all the water comes out.

How Often Should You Drain Your Reverse Osmosis Tank?

The frequency of draining your RO tank depends on the quality of water you want to consume. If you’re not storing a lot of food and drink in your house and you’re using the water for cooking and cleaning, then you should drain the tank every few months.

If you’re storing any food or drinks in your house then at least one time per month would be good.

How Long Does it Take to Drain a Reverse Osmosis tank?

In order to clean your RO tank, it’s important that you first drain the water. This way, you’ll be able to reach all corners of your system and remove any dirt or sediment that may have accumulated over time.

There are a few ways to do this. One is by using a hose and simply waiting for the tank to empty. Another would be to tie a hose to the opening of the faucet at the bottom of your RO unit and let gravity do its job.

The third option is to use a tube from your home’s plumbing system and manually open the valve so the water flows out of your RO unit.

If you find yourself having trouble draining your RO tank, then consult an expert who will be able to help you with any issues.

How do you Empty a Reverse Osmosis Tank?

There are two ways to drain a RO tank:

  1. Water can be drained from the top of the tank and collected in a bucket.
  2. The water can be drained from the bottom and collected in a bucket using a hose.
Reverse Osmosis Troubleshooting Water Continuously flows to Drain

How much water is wasted with reverse osmosis?

One of the most common questions about RO systems is how much water is wasted.

Reverse osmosis uses a membrane with pores that are too small for table salt and other minerals to pass through, meaning that it can take up to five gallons of clean water to produce just one gallon of filtered water.

This sounds like a lot, but there are some steps you can take to minimize the waste. For example, try filling up your bath tub before turning on your system; this will save more than 1 gallon of clean water for each minute it takes for the bath tub to fill up.

The amount of water used will also depend on the size of the tank. For instance, if you have an RO system with a 10-gallon tank, it should use less than 5 gallons of clean water to generate one gallon of filtered water.


Reverse osmosis systems are an excellent way to filter your water. But if not maintained correctly, they can cause serious damage to your pipes and appliances.

Meet the author: Nancy Hernández

Nancy is a yoga instructor and a knitwear designer. She has been teaching yoga since 2013 and is certified by Yoga Alliance. In her spare time, she enjoys traveling, tennis and cooking. “As a mother of three, my kids keep me busy. But spending time with them is really a treat. They are growing up so fast and I do not want to miss anything!” Learn more about Nancy and the rest of the team.