Reverse Osmosis Troubleshooting Guide

Person troubleshooting under a sink with a wrench, Reverse Osmosis guide visible.

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 469-521-9920.

In This Article

NO WATER

SLOW FLOW THROUGH FAUCET

LEAKING MEMBRANE HOUSING

LEAKING RO FILTER HOUSING

LEAKING FAUCET

BAD TASTE OR ODOR

CLOUDY ICE OR MILKY WATER

NOISY DRAIN OR FAUCET

LEAKING FITTING

SYSTEM RUNS CONTINUALLY

ICE MAKER NOT WORKING

FRIDGE DISPENSER NOT WORKING

In This Article

⇩ NO WATER

⇩ SLOW FLOW THROUGH FAUCET

⇩ LEAKING MEMBRANE HOUSING

⇩ LEAKING RO FILTER HOUSING

⇩ LEAKING FAUCET

⇩ BAD TASTE OR ODOR

⇩ CLOUDY ICE OR MILKY WATER

⇩ NOISY DRAIN OR FAUCET

⇩ LEAKING FITTING

⇩ SYSTEM RUNS CONTINUALLY

⇩ ICE MAKER NOT WORKING

⇩ FRIDGE DISPENSER NOT WORKING

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	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.

Learn more about resolving slow water flow issues.

Man drinking water from a glass in a bright room.

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

Hydro Guard Reverse Osmosis System 50 GPD HDGT-45 HDGT-45

This is an exceptional reverse osmosis drinking water system, renowned for its outstanding filtration performance. This RO unit ensures 50 gallons per day of filtered water Equipped with a premium T.F.C. reverse osmosis membrane, it incorporates a sediment pre-filter, carbon post-filter, and an in-line polishing carbon filter, guaranteeing quality drinking water for your entire household.

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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.

SHOP ALL

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	Clean and sanitize the RO system
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

RO Maintenance and Sanitizing Kit for Most Standard RO Systems MSKIT-RO

RO Service Kit INCLUDES:

1x PFW190 Filter Wrench
1x SS25RO RO System Sanitizer Packet
3x 151121 O-rings for Filter Housings*
1x 1013501 Silicon Lubricant for O-rings

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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
1. Air gap faucet	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

Microline TFC-400-ESP RO System 50 GPD TFC-400-ESP

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Proven, High-Quality System

Designer Chrome Faucet

High-Flow 3/8" Tubing to Faucet

4-Stages of Filtration

Compact 3.2 Gallon Storage Tank

Airgap Faucet Connection

50 Gallons Per Day

Made in USA

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AXEON Solo I All-In-One 4-Stage 50 GPD RO System (211470)

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Compact, Space-Saving Design

Standard Chrome Faucet

High-Flow 3/8" Tubing to Faucet

4-Stages of Filtration

Standard 4.4 Gallon Storage Tank

Airgap Faucet Connection

50 Gallons Per Day

Designed in USA, Made in China

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GRO 1:1 RO High Efficiency 75 GPD Drinking Water System (GRO-75GPD)

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Advanced Filtration, Quick-Change Filters, & Conserves Water

Designer Chrome Faucet

High-Flow 3/8" Tubing to Faucet

4-Stages of Filtration

Standard 4.4 Gallon Storage Tank

Air Gap and Non-Airgap Faucet Connection

75 Gallons Per Day

Made in USA

Free Shipping

Frequently Asked Questions

Why is my reverse osmosis system not producing any water?

A few common culprits cause no water flow: the water supply could be turned off, the RO storage tank may be improperly pressurized (it should sit at 5–7 psi when empty), or a clogged pre-filter or membrane could be blocking flow entirely. Other possibilities include a closed ball valve on the storage tank, a crimped product line, or insufficient incoming water pressure, which needs to be at least 40 psi for the system to function properly. Checking pressure and filter condition first usually narrows down the cause quickly.

Why is water flowing slowly from my RO faucet?

Slow flow is most often caused by a clogged pre-filter or post-filter, low air pressure in the RO storage tank, or a membrane that's fouled and overdue for replacement. Incoming water pressure below the 40 psi minimum can also slow output significantly. If the system or filters are newly installed, allowing 4–6 hours for the system to fully pressurize and fill can resolve temporary slow flow on its own.

Why does my reverse osmosis water taste or smell bad?

Bad taste or odor usually points to an exhausted carbon filter, a membrane that's no longer rejecting dissolved solids effectively (typically below 80% TDS rejection), or a system that needs sanitizing due to bacterial buildup. It can also happen if the system sits unused for too long — RO water shouldn't go undrained for more than 5 days, since stagnant water in the lines can affect taste. Replacing the exhausted filter or membrane and running a sanitizing cycle usually resolves the issue.

Why does my RO system run continuously instead of shutting off?

A system that won't stop running is commonly caused by a malfunctioning automatic shut-off valve, low incoming water pressure, or low air pressure in the RO storage tank. It can also result from a ruptured storage tank bladder, a worn-out flow restrictor in the drain line, or a membrane that wasn't installed correctly. Checking tank air pressure and the shut-off valve first is the quickest way to diagnose the cause.

Why isn't my ice maker getting water from my RO system?

This usually comes down to the shut-off valve to the ice maker not being open, the ice maker switch inside the refrigerator being set to off, or the RO storage tank simply not having enough water available. If the fridge dispenser also isn't producing water, holding down the dispensing handle for 2–3 minutes can help draw water through the system; if nothing comes through, the RO unit itself should be checked for proper flow.