11 Causes Why is my reverse osmosis system slow?

Although reverse osmosis systems are notorious for their high water flow rates, sometimes they can be slow.

While you are thinking, why is my reverse osmosis system slow? There are several potential causes that you can troubleshoot yourself.

In this blog post, we’ll explore 11 possible reasons why your RO system might be slow and give you some tips on how to fix the problem.

We’ll also discuss what to do if you think your RO water system might not be working correctly.

So if you’re struggling with a slow reverse osmosis system, keep reading!

11 Reasons your Reverse Osmosis system slow

1. Clogged Filter Can Slow RO Water Flow

A clogged filter can cause reduced gallons of water flow and restrict the reverse osmosis system from operating at total capacity.

If you suspect your drinking water filter is clogged, try flushing it out with water or replacing it.

2. Clogged RO Membrane Slows Water Flow

If the RO membrane is clogged, the unit might not push gallons of water through and provide some water at a slow rate.

This is usually caused if your RO uses cloudy water containing more solid contaminants than average.

To fix this problem, you need to replace the reverse osmosis membrane.

3. Pressure in Tank Might be Low

The pressure gauge at the faucet depends on how much water is in the RO tank.

The holding tank might be empty if you have recently changed filters but are still experiencing low water pressure.

You can fill it up by running a continuous water cycle through your reverse osmosis system.

4. Water Supply Line Might be Clogged

Suppose you have recently installed new fresh water supply lines or are using old supply lines that have been exposed to specific contaminants.

In that case, it could cause reduce the performance of drinking water treatment.

You must flush the lines and check the RO unit to see if this fixes the problem.

5. Air in Reverse Osmosis Water system

When the filter is changed, the air bladder can enter the reverse osmosis system causing reduced water filtration and low pressure.

If you recently changed your filter housing and are still experiencing low or no water flow, check that the air gap on your faucet isn’t clogged.

Check with a flashlight to see if the water is running out of the air gap. Turn off your system and remove the faucet head to clear any obstructions if it isn’t. 

The RO can remove chlorine, lead, dissolved solids, and other harmful contaminants from tap water. It’s no wonder that the water softener is an excellent investment for any home.

This device uses air pressure in the RO tank to maintain consistent pressure so you can enjoy tasty water production all day long!

6. The reverse osmosis low water pressure

Slow Presser

If the incoming water pressure is low, it will cause your reverse osmosis system’s pressure to be lower.

This is usually due to the main water line in your home being too small to support the RO system.

You can fix this by getting a booster pump or pressure regulator.

7. Kink in Water Line Can Disrupt Flow

If you have a kink in your water supply line valve, it can cause low pressure and restricted water flow; try removing it and straightening the hose.

If a hose has a kink, it can also cause a restriction in filtered water treatment.

8. Reverse Osmosis tank pressure when full

When complete, the normal water pressure inside the reverse osmosis storage tank is significant. If the fresh water in your tank is under high pressure, it will cause reduced water flow.

You can fix this problem by draining your RO tank.

9. Reverse Osmosis system pressure low shut off the check clean water supply valve.

If the shut-off device for your reverse osmosis system is not working correctly, it can cause reduced water flow.

If you suspect that your shut-off check air valve isn’t working correctly, try to replace or repair it

10. Low Water Pressure from the City

Suppose the city reduces your clean water pressure from too many people using a water tank. In that case, it can cause low pressure and restricted water flow.

This is usually a temporary problem that the city is trying to fix.

11. Ruptured Tank Bladder in the RO System

If your holding tank bladder ruptures, it can cause reduced water, slow flow, and low pressure. If you suspect your bladder has burst, you can quickly fix this problem by replacing it.

Here are the top 11 reasons why is your reverse osmosis system slow. – With solutions.

If you are experiencing low water pressure, use this list of common root causes and solutions to troubleshoot your RO system.

How to Determine Water Flow Rate of Your Reverse Osmosis System

Step 1: First, ensure the incoming water line is turned on.

Step 2: Check the water pressure at any point in the incoming water line before entering your reverse osmosis drinking water system for a noticeable pressure drop.

Step 3: If there’s good water flow, the problem is most likely caused by a malfunction of the reverse osmosis drinking water system.

If there is no drop, the problem could be caused by something before your RO water filtration.

Step 4: If you experience reduced water flow and low pressure, turn off the RO water system and check the water supply valve.

Then check every component of your reverse osmosis drinking water system for a source of the problem, which could be any one of the following:

  • Dirty filters, especially pre-filters
  • Reverse osmosis membrane housing
  • Sediment water filter
  • RO pre-filter housing
  • Shut off the device on the RO unit
  • Air gap on your faucet or drain line

Step 5: If the problem is a dirty pre-filter or low-pressure tank, you can fix it by replacing either.

To get desired performance, you should know when to change your RO water filter.


How to increase water pressure in the RO system?

You can do several things to increase your water pressure volume if you’re experiencing low pressure or restricted water flow.

The easiest solution is to get a booster bicycle pump or pressure regulator.

They work by increasing your incoming water pressure, giving your RO system more pressure.

Why purge reverse osmosis for 24 hours?

Purging your RO system for 24 hours is necessary because there will be air pressure inside. It needs to be removed before final testing and use.

This can cause the membrane to dry up, crack, and shorten its life span.

To purge your system, simply fill your reverse osmosis storage tank pressure up entirely to the top with water and let it sit for 24 hours.

After purging for 24 hours, you can test your RO system to ensure it’s working.

What is the minimum water pressure for the RO system?

The minimum water pressure required for your RO water filtration is 25 to 70 psi (pounds per square inch).

 If the pressure exceeds this, it may cause restricted water flow or reduced pressure.

You can either increase the incoming water pressure or install a booster pump when there is no pressure.

Does a RO system produce alkaline water?

Yes, your system will make alkaline water after the reverse osmosis water.

This is because the RO membrane separates water molecules from ions, which increases its acidity.

It can easily remove chlorine, lead, harmful contaminants, and various dissolved solids from tap water and produce excellent water.

The water softener uses air pressure to maintain a consistent force in the reverse osmosis tank.

When making this type of water, make sure to add minerals back into your filtered water.


Although reverse osmosis systems are notorious for their high water flow rate, sometimes your reverse osmosis system can be slow.

Suppose you’re experiencing low water pressure or a lack of flow from your RO system.

In that case, there are several potential causes that you can troubleshoot yourself, and use this list of common root causes and solutions to troubleshoot your RO system.

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