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5 Causes of Reverse Osmosis Low Water Pressure (and How to Increase)

Scott Winfield
Last Updated on
by Scott Winfield

RO water flow might get slower than normal for multiple reasons such as clogged filters and membrane, lower pressure of air in the tank, ruptured RO tank bladder and problem in your water supply pipes.

Why Is My Reverse Osmosis Water Flow Slow
Reverse Osmosis System

Some other causes might include high pressure inside a full tank, faulty water supply line valve and low water pressure in the city water line.

1. Clogged RO Filters Or Membrane Can Cause Low Water Pressure

This is probably the most common reason for slow flow rate of water in your RO system. As the filters are continuously separating harmful contaminants, microscopic dirt particles, and other impurities from the supply water, the filters may get all dirty and clogged after a few months.

Your RO Membrane and Filters are Clogged

Clogged filters will restrict regular water flow, and you might not get any water at all if the situation is extreme. You can avoid this issue by changing your filters annually. In case the water in your area is extremely contaminated, try changing the filters every six months.

It’s the same for your Reverse Osmosis membrane. This membrane is very fragile and requires replacement every 6 to 24 months, depending on the water condition and the model of your system.

When the membrane is clogged, your RO system will take 4 to 6 hours (instead of the regular 2 to 4 hours) to give you clean drinking water. To ensure optimal water flow, maintain or replace the membrane regularly.

In case you don’t know the required regular maintenance schedule for your particular system model, contact a local technician to guide you.

2. Ruptured Bladder Tank Can Cause Slow Water Flow

There are multiple reasons why the holding tank bladder of RO Systems might rupture. Mostly it happens due to the lack of regular maintenance.

The RO Tank Bladder Is Ruptured

Detecting a ruptured tank is easy. Check if the water flow rate decreases after providing one cup or 8 oz of water at normal pressure.

Unfortunately, you can’t repair the tank of your RO system.

If you’re facing slow flow due to a ruptured RO bladder, you need to take it to an expert and replace the entire storage tank with a new one.

3. Problem in Water Supply Lines

What happens when your garden hose gets kinked? You receive slow water flow, or sometimes it just completely stops. Similarly, if you have a twisted or crimped water line somewhere in your RO system, the water flowing will become slower than regular.

Kinks in Your Supply Lines

To detect this issue, check out your water supply lines and see if the hoses are correctly oriented. If you find any twisted hose, simply straighten it using your hands. While you’re on it, inspect the water supply valve as well and make sure it’s fully opened.

4. Air Pressure Inside the RO tank Is Low

Inside your RO system, there’s a pressurized tank that needs to maintain a certain amount of air pressure to provide an optimal water flow.

Air Pressure Inside the RO tank Is Low

In general, the pressure should be 6 to 8 psi without water inside the tank. So, if you’re receiving slow water flow, low pressure inside the tank might be the reason.

Thankfully, the process of checking the air pressure inside the tank is easy with the Schrader Valve. It’s placed under a blue color cap on the side of the water tank.

You can also check the pressure with a pressure gauge. For this, empty the water and measure the pressure with the gauge.

If the air pressure is lower than standard, use the air pump and keep adding air slowly inside the tank. Make sure you do the task carefully as extra pressure (> 8 psi) might damage the RO tank.

5. Fluctuating Water Pressure

Reverse Osmosis system requires around 30-40 psi of normal water pressure to operate and 60 psi to maintain optimal water flow. Occasionally, the water pressure in your system might fluctuate temporarily due to some inconvenience like maintenance work or other local water utility company issues.

This problem is usually temporary, and the pressure should be back to normal in a few days. However, if the low water pressure issue continues, contact your local utility company to solve it.

Fluctuating Water Pressure

The Correct Pressure for Reverse Osmosis Tank

As you might know, RO tanks contain two different compartments for air and water. Both the compartments must maintain a standard pressure to function properly. Here’s how the system works.

The air is pressurized inside the air compartment, and it pushes the water through the faucet once you turn it on. Now, as I have mentioned, the storage tank pressure should be 6 to 8 psi when it’s empty.

Once water fills up, the tank pressure increases, and the increased pressure is later released when the water flows through the faucet. For a tank full of water, the tank pressure should be at least 30 psi.

Most RO units feature a shut-off valve that stops the water production if the pressure in the tank exceeds this minimum water pressure value. The optimal water pressure for your system is between 25 psi and 70 psi.

How to Increase Water Pressure in an RO System?

To increase the water pressure in your RO system, clean your filters regularly, replace the membrane annually, replace the ruptured tank bladder, monitor the incoming water line, and maintain the optimal water and air pressure inside the storage tank.

If the slow flow rate continues after these fixes, you have to use electric booster pumps, install a sediment filter, add a flush kit, or get a new secondary water tank. Go through the detailed discussion below and see which one works for your system.

1. Ensure Regular maintenance

This might seem like a cliche, but following maintenance, the routine can actually solve most of the common issues of your Reverse Osmosis system. For this:

  • Change your RO filters and membrane annually and inspect them weekly to check the level of dirt and contaminant
  • Examine the storage tank, drain tube, feed water valve, and drain line regularly
  • Use a PSI gauge or the lever under the blue cap of your system to keep the water and air pressure checked
  • Take your unit to an expert if you detect any leaks or disrupt the flow of water

2. Use Electric Booster Pump

It’s probably the easiest way of improving the pressure and performance of your Reverse Osmosis system. If you add a booster pump, it will increase the water production rate, boost the storage volume of the pressure tank, improve the water flow rate through the faucet and filter more contaminants.

In short, it’s an upgrade of the entire system. With a booster pump, the feed pressure might increase up to 100 psi. There’s a screw on the pump to adjust and lower the pressure allowing you to avoid leaks and other related problems.

3. Install Sediment Filter

If your RO filters get clogged frequently, whole house sediment filters will be a great use. Sediment filters are made of strong metal to last forever, and they can increase your RO water pressure by:

  • Improving the longevity of the filters
  • Bringing clogging down to a minimum
  • Reducing wear and tear of the system
  • Increasing the efficiency of the filters and overall system

4. Get a Secondary Water Tank

Installing a secondary water tank will improve the flow rate of the faucets and other outlets of your place. The math is simple, two tanks will have twice the water capacity and flow rate.

Secondary tanks are available in compact sizes allowing you to install them under the faucet or inside a cupboard. Moreover, installing these tanks is also super easy, and you don’t need any professional help for the task.

If you’re facing low feed water pressure issues, installing a secondary tank will definitely come in handy.

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Scott Winfield
Scott Winfield
My name is Scott Winfield and researching and writing about water filters and other strategies to purify water has become my full time passion in recent years. I'm glad that you found our site and you can look forward to authoritative and well researched content here to help you get the best in water.
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