Reverse Osmosis Troubleshooting Guide

Man fixing RO system

How to Troubleshoot Your Reverse Osmosis System

If your RO system is in need of repair, our "RO Troubleshooting Guide" can assist you in diagnosing issues with your reverse osmosis (RO) water filtration system.

From the list below, select the problem you're experiencing. We provide possible solutions for that RO issue. Please understand that the solutions offered are given as a general guideline, and we strongly recommend you consult your specific RO systems’ owner’s manual and/or local water treatment specialist.

If you purchased your RO system or filters from ESP Water Products, our customer support reps are available Monday through Friday, 8 am to 5 pm (Central Time) to answer questions and troubleshoot over the phone at 877-377-9876.

Reverse omosis troubleshooting guide
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Common RO Troubleshooting Issues

No Water Coming Out of RO System

Potential Reasons Solution

1. Tank improperly pressurized

Set tank pressure at 5-7 psi when empty

2. Over pressurized tank

Check RO storage tank optimum pressure 5-7 psi when empty

3. Water supply turned off

Turn water supply on

4. Low water pressure (40 psi min)

Call for assistance – may require pressure pump

5. Pre-filter clogged

Replace pre-filter (how to replace filter)

6. RO membrane damaged or clogged

Replace membrane (how to replace membrane)

7. Product line crimped

Remove crimp in line

8. Post-filter clogged

Remove post-filter

9. Ball valve on RO tank closed

Open RO tank ball valve

10. Check valve/restrictor valve clogged

Replace check valve/restrictor

Slow Water Flow from RO Faucet

Potential Reasons Solution

1. Pre-filter clogged

2. Post-filter clogged

3. Low air pressure in RO tank

Raise pressure in RO storage tank to 5-7 psi

4. Low water pressure (40 psi min)

Replace RO membrane

5. Fouled RO membrane

Allow 4-6 hours for system to fill

6. Need new system, filters, or membrane

Read more about resolving slow water flow issue

Leaking Reverse Osmosis Membrane Housing

Potential Reasons Solution

1. Threaded end cap leaking

Lubricate o-ring with silicone sealant and retighten. If leak continues, replace with new lubricated o-ring.

2. Cap or body of housing leaks

Check for any cracks in membrane housing and/or housing cap – if cracked or damaged replace both cap and housing

Leaking RO Pre-Filter or Post-Filter Housing

Potential Reasons Solution

1. O-ring not seated properly, or filter housing cap not screwed on tightly

Is o-ring in the groove? Check for damage and if found, replace o-ring. If dirty, clean and lubricate. Retighten lid. Hand tighten only.

2. Housing damaged

If any detectable damage or cracks, then replace housing and lid

Leaking Reverse Osmosis Faucet

Potential Reasons Solution

1. Fitting Leaks

Tighten fitting – make sure tubing is pushed into fitting /base of faucet stem

2. Leak at base of brass stem

Replace faucet 

3. Spigot drips

May require faucet repair or new faucet

4. Overflow at air gap

Purchase a new faucet

RO Drinking Water Systems

Under-sink reverse osmosis filtration is an economical way to provide your household with clean, great-tasting drinking water.

Whether you're looking for an RO system with a proven record and reputation, one with a low price point, or a system that's easy to maintain, we offer a variety of options for you.

Filtered Water Still Has Bad Taste or Odor

Potential Reasons Solution

1. Bad membrane

Replace the RO membrane if TDS rejection is below 80%

2. System needs sanitizing

3. Exhausted filter

Replace the RO water filter

4. Not enough water used

Drain system – do not allow water to remain unused more than 5 days

Cloudy Ice or Milky Colored Water

Potential Reasons Solution

1. Bad Membrane

Replace the RO Membrane

2. Water supply

High oxygen content –Tiny bubbles – will go away with use

3. System or filters are new

Air in lines – will go away with use

Noisy Drain or Faucet

Potential Reasons Solution

A little noise is common with air gap faucets. Check your owner's manual to be sure air gap is installed properly. Learn more about air gap vs. non-air gap faucets.

And some RO drinking water systems (such as the TFC-400-ESP) come with a facuet that can be used with air gap or non-air gap.

Air in systems may take up to two weeks to be purged from system under normal use.

2. Drain tube

Check drain line from faucet runs downhill to drain saddle clamp. Loops, bends, dips or kinks can cause noise.

Leaking Fitting

Potential Reasons Solution

1. Fitting damaged or cracked

Replace fitting

2. Tubing not pushed securely into fitting or threads not properly installed

Check tubing installation & thread installation.

RO System is Continually Running

Potential Reasons Solution

1. Automatic shut off valve not working

Replace automatic shut off valve – be mindful of where the four lines are removed and reinstalled.

2. Low incoming water pressure

Increase water pressure – minimum required 40 psi

3. Low RO storage tank air pressure

Check air pressure in RO Storage tank – optimum 5-7 psi when empty

4. Damaged or ruptured RO storage tank bladder.

Replace RO storage tank

5. Flow restrictor in drain line worn out.

Replace the flow restrictor that matches membrane capacity

6. Membrane incorrectly installed

Check membrane installation instructions

Ice Maker Not Working

Potential Reasons Solution

1. Shut off valve to ice maker not open.

Open shut of valve

2. Ice maker in handle in refrigerator in off position

Place in on position

3. No water in RO storage tank

Check RO unit

No Water Dispensed From Refrigerator Door

Potential Reasons Solution

Reservoir in refrigerator is not full

Hold down refrigerator water dispensing handle for 2-3 minutes to draw water through system. If no water is produced check RO unit for water flow. Learn more about connecting your RO system to a refrigerator or ice maker.

Top-Selling Reverse Osmosis Drinking Water Systems

Reverse Osmosis Technical Tips

How to Change RO Filters

Learn how to replace your RO systems' filters and membrane with step-by-step instructions.
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How to Install a Reverse Osmosis System

Clear, concise instructions on how to install an under-sink reverse osmosis filtration system yourself.
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How to Connect an RO System to Fridge or Ice Maker

Tips for connecting your RO system to a refrigerator water dispenser or ice maker. Get step-by-step guidance for optimal results.
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