If your reverse osmosis faucet in St. Louis suddenly smells wrong, the cause is often something close to the faucet, the storage tank, or the drain. A smell is a clue, not a diagnosis, so work through the checks below in order and write down what you find before you change anything.
Compare the Smell at Other Taps
Run the cold tap at a sink that does not have the RO faucet, then smell the water. If that plain tap water has the same odor, the smell is coming from your supply and the filter is passing it along. If the plain tap smells fine and the RO water does not, the problem is inside your system or at the faucet. Also check hot water at another sink. A rotten egg or sulfur smell that only shows up on the hot side points toward the water heater or building plumbing, not the RO unit.
Check the Faucet and Aerator
Unscrew the aerator on the RO faucet, if it has one, and rinse it under clean running water. Wipe the spout and the handle with a clean cloth. Odors can build up in small parts that rarely get cleaned. Put the aerator back and run the water again before judging the smell.
Look at the Storage Tank
A storage tank that has sat unused for a long time can hold water that has gone stale. If you have been away, or the faucet has barely been used, draw off a good amount of water until the tank refills, then smell a fresh glass. Stale water usually smells flat or slightly off, and it should clear once the tank has cycled. If the smell comes back quickly after you draw the tank down, the cause is more likely upstream or in the storage tank itself, which deserves a closer look by a qualified local plumber.
Consider a Recent Filter Change
A new filter can cause a short-lived smell. Fresh carbon can release fine particles and a mild carbon or plastic odor for a while after installation. Check that every cartridge is seated fully, that the housings are closed, and that you flushed the system as the instructions describe. Then note the install date in your records so you can tell whether the smell started with the change or later. A smell that starts well after a filter change is less likely to come from the new filter itself.
Rule Out the Drain Side
Sewer odor can seem to come from the RO faucet when it actually rises from the sink drain. Put your nose near the drain opening of the sink with the RO faucet. If the smell is strongest there, run water in that sink for a while to refill the trap. A dry trap lets sewer air into the room. Also look at the drain tube from the RO unit and the connection where it meets the drain. Make sure it is clean, not blocked, and not sitting in standing water.
Name the Smell
Describing the smell helps narrow the search. A chlorine-like, sharp, or pool-like smell points toward the city supply or chlorine in the source water. A musty or earthy smell often points toward stagnant water or organic material in the supply, which a water test can help sort out. A rotten egg or sulfur smell usually points toward the hot side, a drain, or a source issue. Plastic or rubber odors can come from new tubing or gaskets and usually fade with flushing. Write down the smell in one or two words so you can compare it later.
When to Stop Drinking and Get Help
If the smell is strong, sharp, or new, stop drinking from the RO faucet until you know the cause. Use another water source you trust in the meantime. Contact your water utility and ask whether there has been any recent change or work on the supply in your area. For plumbing, drain, or storage tank problems, a qualified local plumber can inspect the connections in person. A certified lab can test the water if the smell persists or if you want to know what is in it.
Keep a Simple Log
- Note the smell in one or two words.
- Record whether it appears at the RO faucet only or at other taps too.
- Write down the date of the last filter change and the last time the tank was drawn down.
- Record what you cleaned, flushed, or checked, and the result after each step.
A clear log makes it easier for a plumber, a water utility, or a testing lab to help you quickly, and it keeps you from changing several things at once.