Reverse Osmosis Troubleshooting Guide
How to Troubleshoot Your Reverse Osmosis System
This guide can assist you in diagnosing and troubleshooting 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 that 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.
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 | Call for assistance – may require pressure pump |
4. Low water pressure (40 psi min) | Turn water supply on |
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 | Replace pre-filter (how to replace filter) |
2. Post-filter clogged | Replace post-filter (how to replace filter) |
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 | Call for assistance Learn more about slow RO water flow. |
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 |
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. Defective unit | Replace the RO System |
2. Bad membrane | Replace the RO membrane if TDS rejection is below 80% |
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 |
5. System needs sanitizing |
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. |