Utility disinfectants. Taste and odor are NSF/ANSI 42 territory. Chloramine needs a chloramine-specific listing and usually catalytic carbon.
What’s in the water
Hardness is not iron. Lead is not nitrate. A city list on these pages is only what the city file already printed.
Cities whose files cite hard or very hard water — USGS-style hardness as calcium and magnesium, not a health MCL. A salt softener is the box that actually removes it, and only if the sewer allows brine.
Dissolved calcium and magnesium. Causes scale, soap scum, and spotting. Not an EPA health MCL.
Stains fixtures and laundry orange or red; may be dissolved (ferrous) or already rust particles (ferric). EPA secondary standard 0.3 mg/L.
A primary drinking-water contaminant. Home treatment claims on this site stay on NSF/ANSI 53 or 58 lead-reduction listings for the exact model — not a story about what the filter protects you from.
Acidic water. EPA secondary range is 6.5–8.5. Below that, corrosion and metallic taste are the published effects. Sequence the neutralizer first.
WHO’s 2019 drinking-water review found particles in treated tap and bottled water in many places. That is a published-occurrence finding, not a city-tap count we will invent.
Nitrate (as N) has a 10 mg/L EPA MCL. Point-of-use reverse osmosis can carry an NSF/ANSI 58 nitrate-reduction claim. This page does not diagnose well or farm exposure.
A class of industrial chemicals. Home treatment claims on this site are limited to product-specific NSF/ANSI 53 or 58 PFAS reduction listings.
Rotten-egg odor on many wells. EPA’s secondary odor standard is 3 TON; the gas is not treated by a softener.