Chlorine, PFAS and fluoride: choosing a water filter

Water filters get sold on fear, so let's keep it simple: what's in the water, what each type of filter takes out, and what you actually need.

Whole-house carbon filters

Town water is disinfected, usually with chlorine or chloramine. A whole-house carbon filter at the meter takes most of that out, so showers and baths aren't chlorinated. Carbon block and good GAC filters also reduce PFAS.

Options in the registry: Puretec FilterWall (with a certified installer on the Coast), the Living Whole triple filter and the Zazen range, which publishes its own PFAS testing.

What they don't do

Carbon doesn't remove fluoride. If you want fluoride out, or you want the best PFAS reduction for drinking water, add a reverse osmosis unit under the kitchen sink. RO wastes some water, so keep it to drinking and cooking.

Cartridges only work if you change them. Put the change dates in your calendar when it's installed.

Tank water is a different job

Rainwater needs sediment filtration and usually UV for bacteria, not chlorine removal. Tank water can also be slightly acidic, which matters for your pipes.

Don't forget the pipes

Filtered water still runs through your plumbing. Copper with press-fit joints and Aquatherm polypropylene are the lowest-leaching options. Skip copper if your water's pH is below 6.5, which is common with tank water.

Any filter on the mains has to be WaterMark certified and installed by a licensed plumber.