If you have noticed small black specks in your kitchen or bathroom sink, the first place to look is the faucet aerator, the small mesh screen threaded onto the tip of the spout. Aerators catch sediment and debris that travel through the plumbing, and they can also trap flakes that break loose from worn rubber washers or internal faucet parts. Before you start thinking about your water supply, unscrew the aerator and take a look.
What Black Specks Can Come From
In a St. Louis home, dark particles usually come from one of a few places:
- Sediment or debris from a recent plumbing repair, a water main break, or street work that stirred up material in the lines.
- A rubber or composite washer inside the faucet that is wearing down.
- A water heater, where the anode rod and the tank lining can shed material over time, and where particles may show up mainly on the hot side.
- Carbon fines from a newly installed carbon filter, which often look black and usually clear up after a flush.
- Mineral or iron deposits, which tend to be reddish, brown, or dark and may stain fixtures as well.
A Simple Check You Can Run Today
- Remove the aerator from the kitchen faucet and rinse it over a white bowl or paper towel. If the specks come out of the screen, you have found the source.
- Run only the cold tap for a few minutes, then only the hot tap. If the specks appear on one side only, the water heater or hot water line becomes the likely suspect.
- Run the water into a clear glass held up to a light. Note whether the particles are sparse, frequent, or gritty.
- Check whether the specks also appear at other fixtures, such as the bathtub or an outdoor hose bib.
- Reinstall the aerator and watch for several days. If the specks stop, the cause was most likely temporary.
Hot Side Versus Cold Side
Particles that show up only on the hot side point toward the water heater. Sediment settles at the bottom of a tank, and when the heater fires up or someone draws a large volume of hot water, that material can move into the lines. Flushing the tank according to the manufacturer's instructions can help, and a licensed plumber can check the condition of the anode rod. If you are not comfortable draining a tank yourself, ask a plumber to look at it.
Particles on both sides usually point to the supply side, meaning the city main, your service line, or work done on the street. In that case, a steady flush of the cold tap for a while, followed by another check at the aerator, is a reasonable next step.
When to Test the Water
Most of the time, a clean faucet screen and a flush answer the question. Testing becomes worth the effort when specks keep returning after you clean the aerator, when they come with a change in color, taste, or odor, or when several fixtures show the same problem at once. A laboratory test can identify metals and other constituents that a visual check cannot. Ask the lab which parameters it reports, what sample container it provides, and how the sample should be collected so the result reflects your tap rather than water that has sat in the pipes overnight.
Notes for St. Louis Homes
Many St. Louis houses have older galvanized or copper plumbing mixed with newer sections, and repairs over the years can leave fragments inside the lines. If your home is older, or if neighbors reported similar issues after work on the street, mention it when you contact the city about recent main work. Keep notes on when you first saw the specks, which fixtures they appeared in, and whether a flush helped. That record makes it much easier for anyone looking at the problem to narrow down the cause.
What to Do Next
Clean the aerator, run each side of the tap separately, and write down what you find. If the specks come from the hot side, check the water heater first. If they come from both sides, look into recent street work or a main issue. If the problem continues after several days of observation, call a plumber for an inspection or arrange a laboratory test before you decide on any filtration equipment. Matching the fix to the actual cause keeps the problem from coming back and prevents you from replacing parts that were never the issue.