Water comes first on this site, and the reason is simple: it’s the exposure route with the strongest evidence, the clearest fix, and the only one where you can verify a product’s claim instead of trusting it.

Everything else in a home involves some judgement about how much a given exposure matters. Water is different. You can find out what’s in yours, buy something certified to remove that specific thing, and know it worked. That’s rare, and it’s why this is where your first serious money should go.

Is my tap water safe to drink at home? Start by finding out

Do not buy a filter yet. Almost everybody does this backwards — they buy the filter they saw advertised, then never learn whether it addresses anything in their actual supply.

Two free steps first:

1. Read your utility’s annual water quality report. US systems are required by law to publish one, usually called a Consumer Confidence Report. It lists what’s been detected and at what levels, including PFAS where tested. Search your utility’s name plus “water quality report”.
2. Find out what your pipes are made of. The report tells you about water leaving the treatment plant. It tells you nothing about what happens in the pipe between there and your tap. If the house predates 1990, or you don’t know its plumbing history, that gap is where lead lives.

If you’re on a private well, none of the above applies and testing is entirely on you. Test annually at minimum.

Match the filter to the contaminant, not to the marketing

Filters are not general-purpose. A carbon pitcher that improves taste does very little for dissolved metals. A reverse osmosis system removes almost everything but wastes water and strips minerals. Neither is “better” — they solve different problems.

The rough map:

• Taste, chlorine, odour — activated carbon. Cheap, and the most common purchase.
• Lead, certain other heavy metals, some cysts — carbon block rated for those specific contaminants, or RO.
• PFAS — reverse osmosis is the most reliable route; some high-grade carbon blocks are certified for it. Check the certification, not the packaging.
• Nitrates, fluoride, dissolved solids — reverse osmosis.

The one thing that separates real products from marketing

Learn to check certification, and most of this industry’s advertising stops working on you.

Look for NSF/ANSI certification, issued by NSF, IAPMO or WQA. The standard number tells you what was actually tested:

• 42 — aesthetic effects: taste, odour, chlorine.
• 53 — health-related contaminants: lead, cysts, certain organics.
• 58 — reverse osmosis system performance.
• 401 — emerging compounds, including some pharmaceuticals.

The critical detail: certification is per contaminant. A filter can be legitimately “NSF 53 certified” for cysts alone while doing nothing measurable for lead. The certifier’s public database lets you look up the specific model and see exactly what it was tested against. That lookup takes two minutes and is the single most useful skill on this page.

Phrases like “tested to NSF standards”, “filters up to 99% of contaminants” or “removes 200+ impurities” are not certification. They are sentences.

Budget for the cartridges, not just the machine

The purchase price is the smaller number. Replacement cartridges are the real cost of ownership, and an expired filter is worse than no filter — a saturated carbon block can release what it previously captured.

Before buying anything, work out the annual cartridge cost and whether you’ll realistically keep up with it. A cheap system you maintain beats an expensive one you don’t.

What’s coming in this section

This hub will fill out over the coming weeks with the detailed pieces:

• Under-sink filters compared, with certification checked against each manufacturer’s claims
• Filter pitchers — what the cheap ones do and don’t do
• Reverse osmosis versus carbon: which one your situation actually calls for
• Whole-house filtration, and when it’s genuinely worth it
• How to read your water quality report without a chemistry degree
• The replacement cartridge costs nobody puts on the box

If you want a note when each lands, the home audit checklist comes with occasional updates. No cost.

New here? Start with the overview — it covers what’s worth worrying about across the whole house, and what isn’t.