If your reverse osmosis faucet has slowed to a weak trickle, or the water comes out spotty or sprays in odd directions, the problem is often at the very end of the line, not in the system under your sink. The spout screen, sometimes called an aerator or flow screen, is a small mesh disk that catches grit and mineral flakes. In a St. Louis home where the water supply can carry sediment after main work, or where hard water leaves deposits behind, that screen can clog over time. Cleaning it takes a few minutes and needs no special parts.
Confirm the screen is the likely cause
Before you take anything apart, rule out the other common causes. A faucet that sputters or spits air is usually a separate issue, so check that first. If the flow is weak only at this faucet and the rest of the house runs normally, the screen is a good suspect. If the trouble is in the system itself, cleaning the screen will not change much, so keep that in mind as you go.
Gather what you need
- A towel or soft cloth to protect the sink and the faucet finish
- A small bowl or cup
- Mild household vinegar
- A soft brush, such as an old toothbrush
- Pliers wrapped in tape, only if the tip is stuck tight
Shut off the water first
Reverse osmosis faucets usually have a small shutoff valve on the sink base or on the line near the storage tank. Close that valve, then open the faucet briefly to relieve the pressure in the line. Hold a towel under the spout. Even with the valve closed, a little water may still drain from the lines, so expect a small drip.
Remove and clean the screen
- Unscrew the outer spout tip by hand, turning it counterclockwise. If it will not move, wrap it in a towel and use gentle pliers.
- Pull out the inner screen along with any small washer or rubber seat. Note the order of the parts, or photograph them with your phone, so you can put them back correctly.
- Rinse the parts under warm running water. Push water through the screen from the back side to dislodge particles.
- Soak the screen in vinegar until the crust loosens, then scrub gently with the soft brush. Do not use steel wool or abrasive pads, since they can scratch the metal and leave more surface for deposits to cling to.
- Rinse every part well before you reassemble anything.
Reassemble and test
Put the parts back in the same order, tighten the tip by hand, then open the shutoff valve slowly. Run the faucet and watch the threads for leaks. Let the first few seconds of water run into a container and discard it, since air and loose debris often come out first. The flow should now look steady and full.
When cleaning does not help
- The flow stays weak after the screen is clean, which may point to a restricted line or a problem with the system itself
- Water leaks from the threads, which may mean a worn washer or seal
- The faucet spits air for a long time, which calls for a separate check
- The deposits return within a short time, which suggests your water carries a lot of minerals and the screen will need regular attention
Understand the white crust
The white or chalky crust on a screen is often calcium or magnesium carbonate, the same minerals that build up as scale on kettles and shower heads. A reverse osmosis system removes much of this from the water before it reaches the faucet, but some residue can still form on metal parts over time. Cleaning the screen deals with the buildup you can see. It does not change the water itself, and it does not tell you what the water contains. If you want to know what is in your water, a home test is the right next step.
Make cleaning a habit
How often you need to clean the screen depends on your water and how much the faucet gets used. Two homes on the same St. Louis street can see very different results. Write a short note on the calendar each time you clean it, and check the screen whenever the flow changes. Over a few cycles, that note will show you a pattern and tell you when to check again.