If you need more storage space for water from your reverse osmosis system you can purchase a pressurized tank to store extra water for increased flow as the water in an extra tank remains available for immediate use. The water stores inside in a butyl bladder with a spout to enter and leave the tank. Pressurized air helps to move the water to your faucet once you are ready.
Though many people want a small tank to save on space, you may need a larger tank because of the pressurized air which can take up quite a few gallons of space. A four gallon tank may only hold about two and a half gallons of water because of space needed for pressurized air. Most tanks have an air pressure valve at the bottom and require maintenance to keep their right pressure range in the tank.
Do not let this information scare you! As with all things you learn, a little information will help you decide the right tank for your needs. We did all the research to save you time and energy and below we will provide a question and answer section to help you better meet your needs.
Best Reverse Osmosis Water Tanks
Tank RO keeps your water healthy using 100% food-grade material in a post cured diaphragm without adding chemicals to your water. This tank saves you money by including a free tank valve designed to for 1/4 inch quick connect setup. As this tank holds up to 4 gallons, you can hold up to 2.5 gallons of water to have on tap when you need it. If you need a larger size, the brand also makes a 6 gallon tank as well.
The low price range makes this an economical option for all budgets and has more value as it’s NSF certified with a one year warranty. Also, as the tank comes made of heavy-duty commercial construction with steel, you know this tank will last. The compact 15 x 12 x 12-inch size fits under most kitchen sinks for secure storage.
Finally, the tank includes both a water value for flow and an air valve so you can use an air pump to replace air. Install quickly without a professional for easier access to your water and no added costs. Some customers did not like the included valve, and you may consider purchasing a different valve. Keep track of the air pressure, so your tank lasts longer.
For an even smaller price, you can own the iSpring Tank in two different sizes, including 3.2 gallons and 5.5 gallons. The larger size comes with a larger size but gives you more stored water for quicker access. Though, you may want to consider the amount of space one of these tanks will take up under your sink if using an under-sink filtration system.
The tank is made with FDA approved food-grade material and meets all NSF/ANSI standards. This tank will effectively discharge in both vertical and horizontal positions giving you more ways to store the tank. Next, the tank comes pre-pressurized between 7-10 psi for common use, making this an excellent option for under your sink.
Stainless steel means this tank won’t breakdown and uses an air valve and water valve for easy setup. The 3.2-gallon tank weighs 7.25 pounds and measures 11 x 11 x 14 inches, while the larger size weighs 10 pounds and measures 12 x 12 x 16 inches, and both include a base to hold them up. Some customers complained about water tastes and the short life span of the tank.
Apec not only makes popular water filtration systems but also makes a water storage tank for reverse osmosis systems like this 4-gallon tank. You can also choose a 3-gallon tank if you have less space under your sink. Both tanks are made with FDA approved food-grade bladders and comes certified for quality, safety, and durability.
The inlet/Outlet connection uses a fourth of an inch male pipe thread meant for reverse osmosis application. Each tank comes with a stainless steel water connection, a metal shell, and a sealed brass air valve along with the stand. The tank is supported by a fully enclosed polypropylene and butyl reservoirs for airtight protection against leaks and contaminants.
Next, a leach-free design eliminates the possibility of photos from the tank. The tank measures 11 x 15 inches and weighs 10 pounds and pre-pressurized. Several customers complained that the unit died early what others complained about the taste. To prevent this problem, perform regular maintenance and check the air pressure.
4. Charman 4.0 gal Reverse Osmosis/RO Water Storage Tank
The Charman four-gallon reverse osmosis water storage tank is made of high strength steel with food-grade polypropylene inner liner and a butyl Robert diaphragm. It connects to your water filtration system using a stainless steel 1/4 of an inch NPT connector. It also includes an air storage area and an air valve to pressure water out of the tank.
As the tank it’s for a gallon size, it will hold up to 3.2 gallons of water. The low price will attract many customers for a continuous and stable supply of purified water add a fast flow rate. All of their tanks our CE approved for quality and durability, and they are small enough to fit under your kitchen sink. The tank measures 14.2 x 11.3 x 11 inches and includes the base while weighing just over 7 pounds.
Many people do not like the taste of rubber, which is a strong possibility for reverse osmosis tanks in general. Other customers complain about a short lifespan. Last of all, though the tank is supposed to come with a free valve, so you’re free to purchase your own if you do not like to included valve.
If you are connecting a tank to you may water source instead of to your sink, you may want a larger tank such as this Apec 14 or 20-gallon water tank. These would also work well for larger families who need water available all day. The 14 gallons reverse osmosis tank hold up to 10.7 gallons of water on reserve for convenience.
As with the other tanks, this one includes an FDA approved food grade bladder for durability, safety, and quality. This tank size holds three times more water with improved faucet delivery pressure. It also includes a larger 3/4 inch male and PT inlet and outlet connection for faster tank refills and flow rate.
Furthermore, the tank includes a large water chamber and a coated metal shell. Using a polypropylene liner and butyl diaphragm, you are insured tasteless, odorless, and contaminant-free water from your water filtration system. The takeaways just over 27 pounds and measures 18 x 25 x 18 inches, which means it will not fit under your sink unless you have a giant I’m out of space!
Finally, the tank does not include a connection valve, and you will need to purchase this separately. Ensure the air pressure is accurate, or your tank will hold significantly less water. You may need to flush the tank before used to prevent bad taste.
As the 14-gallon size is a popular size for reverse osmosis tanks, Crystal Clear made one as well. It comes with a side-mounted air valve and a stainless steel air valve. As the sizes larger or you can expect the price to be higher as well then the four-gallon tanks. This tank does come with a one-year limited warranty, though, and a more supportive base.
The tank Waze just over 23 pounds and measures 23 x 15.5 x 15.5 inches, which allows you to hold just over 10 gallons of water. The shape is large enough to work with a full water filtration system but too large to go under most sinks. It includes an air bladder as well as Space for water inside the stainless steel tank.
Next, it includes space 1/4 inch to a 3/4 inch valve but does not include the valve. The pressure rating for this Tank is 100 psi max. This system also comes calibrated with air for immediate use. As with all of these tanks, make sure to flush out before using them.
Finally, as these or steel, they can come with a large dent, which would be frustrating and limit space. Other customers had the internal bladder break rendering the system useless. Very few customers found that the system leaked, so if this has been a problem in the past and you need this size, this is a great option.
If the last 14-gallon tank doesn’t work for you, try the PAE Machinery brand tank, which comes with excellent ratings but does charge a high shipping rate for their less expensive unit. As the tank has a capacity of 14 gallons, it can hold about 10 gallons along with the air needed to push water out.
The tank uses a 1/4 inch stainless steel water connection and a high-grade chlorobutyl diaphragm with a virgin polypropylene liner. It also comes pre-pressurized and pre-charged for immediate use. Also, it weighs 23 pounds and measures 16 x 16 x 23.5 inches long with a base to keep it standing up straight. The max pressure for the tank is seven psi when empty.
Keep in mind the tank does not include the connection valve needed to connect to the filtration system. The nozzle is on the side instead of the top, which could make this more difficult to install depending on your setup, but the installation was effortless. This would make a great addition to your water system.
For those who want a lot of water available on tap, the TankRo offers a twenty-gallon tank to allow about 16 gallons of water at your fingertips or faucet. Of course, the price is significantly higher than a tank that would fit under your sink. Up above, we mentioned the smaller sized tanks by the same brand because these tanks work well and come in a variety of sizes to meet almost all residential needs.
This tank is NSF certified with a one year warranty. Also, as the tank comes made of heavy-duty commercial construction with steel, you know this tank will last. Next, the tank saves you money by including a free tank valve designed to for 1/4 inch quick connect setup. You can use this tank inside or outside as it uses heavy-duty commercial construction with durable deep drawn steel domes and precision welded seams. It’s also coated with a two-part epoxy primer and finished off with a layer of polyurethane
The extra-large tank includes a plastic stand to keep the tank upright. All the materials are FDA food-grade safe to improve taste and reduce odors and contaminants. The bladder is adjustable and made of chlorobutyl rubber and is completely airtight with a virgin polypropylene liner inside for air. In total, this tank can hold 14 gallons of water with air inside. Lastly, the tank weight just shy of 30 pounds and measures 15 x 15 x 29 inches to provide maximum water space.
Amtrol makes massive tanks! These are large enough to work for a mansion and possibly even a hotel but will still work in your residential home. The measurements listed are for their medium tank, but you can choose from 2,4.4, 7.6, 14, 20, 26, 32, 34, and 44 gallons so you can truly customize your water system. It also includes a built-in stand made of the same sturdy material as the rest of the blue tank.
That sturdy material is a high-strength steel shell, and inside they use the standard virgin polypropylene inner liner that will not crack, flake, peel, or chip. A unique positive hoop ring seal secures the diaphragm and liner for extra reliability and strength. This type of system outperforms other styles, so you know you have the best tank available.
Each tank comes pre-pressurized at 38 psi, but its recommended that you always keep it set at two psi below the cut in your pressure switch. Check the tank pressure before installation as the settings should not exceed a 20 psi differential between cut in and cut out. The system measures 15 x 15 x 31 inches and weighs 23 pounds without water.
Finally, the tank may arrive damaged as steel can dent. It comes with an extended warranty, but getting help can cause some issues. This tank does seem to last years longer than other similar tanks.
LiquaGen offers a 40-gallon tank, which is a great size to have enough water for multiple showers and still have water available before losing water. The massive scale will hold the water from your reverse osmosis filtration system. If you prefer a smaller size, this brand also offers tanks in sizes 3.2, 4.5, 6.5, and 20 gallons.
The tank utilizes the stand polypropylene liner and butyl diaphragm to store water and air to get your water to your faucet faster and comes wrapped in steel for water protection. It arrives pre-pressurized and with the finest materials to avoid corrosion in the water chamber, so you don’t have to worry about taste, odors, or contaminants in your drinking water. Thanks to the two-part epoxy primer and polyurethane paint finish, this tank can withstand outdoor or indoor elements.
One issue with this tank is it is much more expensive than the other options available. It does come with a free tank valve and a base to hold the tank upright. Otherwise, this is a problem-free tank ready to give you water fast without issues. You will, of course, have to maintain the psi air levels.
Questions About Reverse Osmosis Water Storage Tanks
How does the reverse osmosis water storage tank work?
The tank holds a water bladder and an air bladder. When you turn on the faucet in your home and demand water, the water is pushed out of the tank’s bladder with air pressure. When the tank is empty of water, it should have around 5 to 10 psi air inside to help push the water out.
Standard reverse osmosis tanks have a hydraulic shutoff valve to stop water production when the pressure in the tanks reaches around 2/3 of the pressure of the tap water that supplies the tank. This is based on your city’s water pressure.
Why doesn’t the tank hold the full amount of water for the size?
Because the tanks need air pressure to push the water out of the tank, you need room inside the tank for air. If you have a 4-gallon tank, you need space for both air and water, so your tank will only have space for about 2.5 gallons of water once you add the air into the equation.
Does the water touch the outer parts of the tank?
No. Your water stays inside of the bladders made of butyl, a type of rubber, and do not touch the plastic or the metal parts of the tank. The water will touch the plastic or metal spout before leaving but nothing else.
How do I service my reverse osmosis tank?
You will need to use a bike tire pump to add in the air to the tank. Check the instructions with your tank for the correct psi for the air pressure for your specific tank. Check the air pressure valve meter on the side or bottom of your tank to make sure you do not add extra air as it will reduce the amount of water your tank can hold. You may need a low-pressure air gauge to check your air as well.
When changing the air, you need to make sure you do not have water in the tank and turn off the inlet water to the unit. Once the tank is empty, add the bike pump and slowly pump in the air, and you need to pump until no more water comes out of the faucet. Next, check the pressure with the low-pressure tire gauge and leave about seven psi in the tank with no water inside. You are done! Just reattach the inlet, and you can move on to the rest of your day.
Here is a good YouTube video demonstrating how to re-pressurize a reverse osmosis storage tank:
Wrapping Up Reverse Osmosis Water Storage Tanks
The Amtrol WX-202 Well Pressure Tank is the best option for most people. It comes in ten different sizes to meet almost everyone’s needs. Whether you need a little extra water stored for one to two people or a tank large enough for a big family, you can find a sturdy option with rave reviews from Amtrol. Also, this brand offers a unique positive hoop ring seal to secure the diaphragm and liner for extra security. Finally, this tank comes with a built-in extra sturdy base, which helps this tank to stand out from the rest.