If the water from a kitchen or bathroom faucet has started to spray sideways, sputter, or slow to a weak trickle, the cause is often a small screen at the tip of the spout called an aerator. In Washington, where local water reports describe the tap water as very hard, that screen can collect mineral scale over time. Homes on private wells in the Missouri River-bottom area may also see iron particles that look like grit or rust flakes. Cleaning the aerator is usually the first step, and it takes only a few minutes.
What an aerator does
An aerator threads onto the end of the spout. It mixes air into the water stream so the flow feels full while the faucet uses less water. Inside are a few small screens and a housing. Because the water passes through tiny openings, anything the water leaves behind, including calcium and magnesium scale or iron particles, can build up there before it shows up anywhere else.
Signs the aerator is the cause
- Flow is weak at one faucet while others on the same home supply run normally.
- The stream splits, spits, or sprays off to one side.
- You see white crust, a yellowish film, or orange flecks around the outlet.
- The flow changes after the faucet has run hot water for a while.
Check it before you replace anything
- Turn off the faucet and wipe the spout dry.
- Wrap a cloth around the aerator to protect the finish, then unscrew it by hand. If it is stuck, a gentle grip with a cloth-covered wrench is enough. Do not force it.
- Take the parts apart in the order you removed them, and lay them on a towel so nothing rolls away.
- Rinse each piece under running water, then scrub the screens with a soft brush.
- Soak metal parts in a mild white vinegar solution to loosen scale, then rinse well. If the faucet has a special coating, read the care notes that came with it before soaking.
- Reassemble the parts, screw the aerator back on, and run the tap.
Run the hot and cold sides separately. If the flow returns to normal, the aerator was the problem. Repeat the check on every faucet in the home, since the same water runs through all of them and the same buildup can start in each one.
When cleaning does not fix it
If the flow stays weak after cleaning, check whether the problem reaches the whole home or only one fixture. Low flow at several faucets points to something upstream, such as a valve that is not fully open, a clogged sediment filter, or a supply issue. On a private well, weak flow across the house can also point to pressure or well equipment, so it is worth looking at those parts of the system before you take apart more fixtures.
Test before you decide what the buildup is
White, crusty buildup usually means hardness. Orange or brown flecks that stain sinks and tubs point more toward iron, especially on a private well. A home test strip can give a quick read on hardness. For iron and for any well water, a certified lab gives a more reliable answer. Private wells are not regulated, so nobody tests them for you. A Washington homeowner on a well should test on a regular schedule and keep the results, so changes show up early.
Keeping scale and iron from coming back
- Clean aerators on a regular schedule instead of waiting for a problem.
- Check bathroom faucets too, since they collect scale the same way.
- Note which faucets clog first so you can watch for patterns.
- Test your water so you know whether hardness, iron, or both are involved before you choose a fix.