Sediment is solid material carried in the water: fine sand, rust flakes from old pipes, and bits of mineral or debris that loosen after work on the line. You rarely see it floating in the water itself. You see it in the bottom of a glass, in a faucet screen, or as a gritty feel in a sink or tub. Before you price a filter, confirm that sediment is what you are dealing with.
Run a glass test
Fill a clear glass from the cold tap and hold it up to a window. Set it on the counter for a few minutes. Milky water that looks cloudy from the start often has trapped air, and that usually clears as the bubbles rise. Specks that settle to the bottom and stay there, or particles you can see drifting in the glass, point to sediment. Repeat with the hot tap. If only the hot side shows it, the problem may sit in the water heater or its supply line rather than the main line.
Check the aerators
Unscrew the aerator, the small screen at the tip of a faucet spout, and rinse it under running water. Look for grit, a dark film, or flakes caught in the mesh. A screen loaded with particles while another faucet's screen stays clean tells you something about where the material is coming from. Check two or three faucets in different parts of the house, including one nearest where the water enters if you can reach it.
Notice the pattern
Write down when it happens, because sediment often follows a specific event. Ask yourself these questions:
- Does it show on one side only, hot or cold?
- Does it appear after the house has been quiet for a while, or right after a large draw such as a washer filling?
- Does it come with lower flow at one or more faucets?
- Did it start after work on the street, the meter, or the main line?
Answers to these questions help a company narrow down the cause, and they give you a fact-based record rather than a memory.
What to ask before you buy equipment
If the glass test and the aerator check both point to particles, ask a treatment company how it would confirm the source. A careful installer should be able to explain whether it would test the water, inspect the line, or recommend a sediment filter on the main supply, and why it chose that route. Ask whether its recommendation rests on a lab result or on a visual check. Ask what happens to the filter as it loads, who changes the cartridge, and how often the company expects that to happen in your home, so the answer reflects your water rather than a guess.
When to stop guessing
If the water is discolored and you cannot tell what is causing it, or if a change in taste or smell comes with it, get a lab test before you rely on any single fix. A test shows what is actually in the water. It does not depend on how the glass looked to you on one morning. For a sense of how to judge companies that offer testing and installation, read the award methodology page on this site.