Water Filtration Assistantby Tyler James, a licensed plumber

What's in your tap water?

A comprehensive guide to your tap water: look up your water district's own report, see what each result means, and find the filter that actually removes it.

  • 3,900 district reports read
  • 700 filters and softeners compared
  • Certified picks first, never ranked by commission

Browse the mapOn a private well?Have your own test results?

Tap water splashing into a glass at a kitchen faucet

How it works

  1. Find your districtSearch your address, ZIP or district name. We check it against the mapped boundary.
  2. See what's in your waterResults read from your district's own report, each explained in plain words.
  3. Get the fix that removes itTreatments and certified models matched to what's in your water.

Browse the map, or search above. Tap a district to see its report.

Your water district

Finding your water district…

Map key
Each color is a separate district Your district No public water mapped (likely private wells) ZIP area (approx.)

Boundaries come from the EPA's mapped service areas, built from state water agency data. Some are estimates; your water bill is the final word. On a private well? Add your well test results.

What's in your water

Your own test results

A utility report covers the whole system, not your home. Pipes and fixtures can add lead or copper, so a test from your own faucet shows what you're actually drinking. Private wells need their own test.

No test yet? Find a state-certified lab (EPA list by state), or ask your county health department.

Where does your water come from?

Search your address at the top to add your district's report. Tested your own tap? Add your numbers and we'll show what they mean.

Enter your results

Type numbers from your utility's report or your own test kit. We'll show what each one means and which systems fix it. Your results stay on this device.

Pick the unit printed on your report and we convert it. Home strips are less precise than a lab, so we show them as estimates.

What do you want out of your water?

Pick any. The treatments and picks below re-sort around your choices.

What works, and why

Picked for your water

Ranked by what they remove and how they're certified. Never by commission.

Certified for your concerns first, then tested-to models (amber). We may earn a commission from “Check price” links; it never changes the order. See every model in the catalog

Learn about your water

Plain answers before you buy: what the numbers in a water report mean, and which filter removes what.

How to read a water report

Legal limit
The most your utility is allowed to have (EPA calls it the MCL, or an action level for lead and copper). Over it, the utility has to fix it and tell customers.
Health goal
The level with no expected health risk (MCLG, or a state public health goal). It is often lower than the legal limit, and for some contaminants it is zero.
ppm ppb ppt
Parts per million, billion and trillion. 1 ppm is 1 mg/L, 1,000 ppb or 1,000,000 ppt. Nitrate is usually in ppm, lead in ppb, PFAS in ppt.
System average
Utility numbers describe the whole system where water enters it. Your home’s pipes can add lead or copper, so a test at your own tap shows what you actually drink.

Below the health goalLegal, above the goalOver the legal limit

What filter removes lead?Look for NSF/ANSI 53 certified for lead. What filter removes PFAS?RO, certified carbon block or PFAS resin. Do I need a water softener?Hard water isn’t a health risk; it’s a choice. Is reverse osmosis water healthy?What RO removes, and what it strips out. What does NSF certified mean?Each NSF/ANSI number in plain words. How often should you change a filter?Rated gallons or months, whichever comes first.
All buyer questions →