How to Pressurize a Reverse Osmosis Tank? Learn Here!
Written by: Gene Fitzgerald // Last Updated: Mar 7, 2023
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Reverse osmosis tanks depend on pressure to function properly.
If your tank’s pressure is too low, you can fix it by pressurizing.
This article provides a step-by-step guide to pressurizing a reverse osmosis storage tank. You’ll also learn how to know if your storage tank is under-pressurized.
Contents
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Key Takeaways
Follow these steps to pressurize an RO tank:
- Close the water supply valve.
- Flush water from the tank.
- Disconnect the tank and take it outside.
- Empty any remaining water in the tank by pumping air inside (use bicycle or similar pump).
- Use a pressure gauge to check tank pressure once empty. Most empty RO tanks require 6-8 psi but confirm first.
- Increase pressure using your pump.
- Reconnect the tank and let it fill.
Step by Step Instructions for How to Pressurize a Reverse Osmosis Tank
We’ve created a step-by-step guide showing how to pressurize a reverse osmosis tank. But first, what pressure range should you be looking at?
The Correct Pressure for RO Storage Tanks
The correct pressure for your RO storage tank is 6-8 psi (remember, you can only measure pressure when the tank is empty). This pressure level varies between tank models, so it’s best to check the label on the tank and read the manual for accurate information. Contact the manufacturer if you’re unsatisfied with the label or manual.
What You’ll Need
You’ll need the following materials:
- Bucket
- Wrench
- Air compressor or pump
- Pressure gauge measuring low PSI (below 10)
Step 1: Close the Water Supply Valve
First, turn off the valve under your kitchen sink to stop water flow into the reverse osmosis system.
Step 2: Flush Water from the Tank
Turn your RO faucet on and let the water run. Do this until the water stops coming out.
Step 3: Disconnect the Tank
Detach the RO tank from the system – removing the tubing – and move it outside.
Further Reading:
Step 4: Empty Any Remaining Water
Open the tank valve (at first, water may gush out, but this flow steadily decreases to mere trickles).
Now you need to use your pump or compressor to pump air into the tank’s Schrader valve. This will cause any remaining water to flow out of the tank.
Step 5: Use a Pressure Gauge to Check Tank Pressure When Empty
With your pressure gauge, measure the tank’s pressure when completely empty. An empty tank usually has pressure ranging between 6-8 psi.
You can measure the pressure with a digital gauge or a tire pressure gauge.
Step 6: Increase Pressure Using a (Bicycle) Pump
If your tank’s pressure is lower than 6 psi, pump air into the valve to increase the pressure to about 7 psi. A bicycle pump is the easiest tool you can use to achieve this. Air compressors can be used, too, just to ensure you don’t overpressurize the system. Overpressurizing can lead to severe problems.
Step 7: Reconnect the Tank and Let It Fill
After pressurizing the RO tank, the next step is to reconnect it and let it fill (remember to open the feed water valve).
How Do You Know When Your RO Storage Tank Is Under-Pressurized?
These are a few signs that your RO storage tank has low pressure:
- RO system drains constantly: If your storage tank is under-pressurized, water might continuously flow down the drain. That’s because there isn’t enough backpressure to trigger the automatic shut-off valve.
- Slow or no water flow from the RO faucet: This also often happens when your storage tank pressure is low. The tank would not have enough pressure to push filtered water up your faucet.
- Low psi reading: You could also measure the tank pressure of course.
Reasons for Low Pressure in a Reverse Osmosis Tank
Low pressure in a reverse osmosis tank can be caused by the following:
- Bad RO membrane: Membranes get clogged when they’re overwhelmed by filtering bad quality water (or when they’re old). This clogging may restrict water flow into the tank, leading to low pressure. To avoid this, replace your reverse osmosis membrane when due and add extra pre-treatment system (like a softener) if need be. By the way, the same goes for your pre-filters. If they are clogged, water cannot flow into the RO tank.
- Bent tubing: Bent tubing may cause a drop in pressure, leading to low water flow. If you notice a slower flow rate, check all your tubing and straighten any bent lines.
Other reasons for low pressure in an RO tank include:
- Membrane not well seated
- Tank is just empty
- Clogged flow restrictor
- Tank, feed water, or leak detector valve closed
- Ruptured bladder inside of tank
- Low feed water pressure
What Happens If RO Tank Pressure Is Too Low or High?
Having your RO tank pressure too high or too low has consequences for your entire reverse osmosis system.
- With too low pressure, you can expect slow or no water flow from the RO faucet because the pressure is insufficient to push out the water.
- Also, with low pressure, water may continuously flow down the drain. As a result, your RO system would waste a lot of water.
- With tank pressure too high, your water storage will refuse to fill up all the way. You’ll also probably see more water flowing down the drain.
When Do I Need to Replace My Bladder Tank Altogether?
You’ll need to replace your reverse osmosis tank when the air bladder ruptures or some other unfixable thing happens.
These are some signs that your air bladder is ruptured:
- Rapid drop in water pressure from the RO faucet even after repressurizing the tank
- Leaks at the tank
- Unstable water pressure
- Clear signs of corrosion on the tank’s exterior
- Excessive air in the plumbing system
You should also replace your bladder tank when it’s old, or has a reduced capacity in general.
How to Solve RO Storage Tank Problems for Good? Go Tankless!
RO systems are either tank or tankless systems. Tankless systems have no use for storage tanks, and that’s an automatic solution to all tank-related problems!
Because there’s no water stored anywhere, tankless systems need to be fast. They use pressure pumps that help them push water up your faucet and meet up with your water demands.
One of the downsides to tankless reverse osmosis systems is that they’re often considerably more expensive than tan-based units.
What Is a Reverse Osmosis Tank and How Does It Work?
A reverse osmosis tank is a storage tank that collects reverse osmosis water after filtration. Reverse osmosis systems without pumps need a storage tank because reverse osmosis is a slow process (it purifies water one drop at a time). RO tanks make the system more practical by ensuring that there’s always water available whenever you turn on your faucet.
RO tanks are hydropneumatic, meaning they hold both water and pressurized air. The RO tank contains an air chamber and a water chamber separated by an air bladder.
As the RO system fills filtered water into the tank, the weight of the water compresses the air chamber, increasing the pressure. On opening the faucet, the built-up pressure pushes the water out of the tank and into your faucet.
Because of the air chamber within the tank, RO storage tanks do not need a delivery pump or booster to work.
Backpressure from the tank is what shuts an RO system off once said pressure has reached a certain level.
If you have any questions about how to pressurize an RO tank please don’t hesitate to leave a comment below!
About the Author Gene Fitzgerald
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