The residential water treatment index

Look it up before you buy it.

Every symptom, contaminant, certification, and real ownership cost — indexed, verified against official databases, and organized so you can diagnose before anyone sells you anything.

POPULAR: PFAS Water smells like sulfur Orange stains Do I need a softener? Read my test report
238
guides & reviews
23
interactive tools
✓ 412
certification claims verified
Jul 18
last verified update
START HERE

Start from your situation

Not from a product list. The right treatment depends on your water — these four doors lead to different answers.

01 · CITY

I’m on city water

Your utility treats it — then it travels through mains and your pipes. Start with your water report.

Find your report → 02 · WELL

I’m on well water

You are your own utility. Iron, sulfur, bacteria, hardness — diagnose by symptom cluster.

Well owner’s guide → 03 · HARD

I have hard water

Scale, spots, dead appliances. Verify your hardness before any dealer sizes anything.

Test & size it → 04 · REPORT

I have a test report

The PDF is in your hand and half of it is red. Decode every line against real thresholds.

Interpret my results →
LIVE TOOLS & DATA

Try the Index — right here

Not screenshots of tools. The tools. A working converter and a slice of the certification database, live on the homepage.

Water Hardness Converter

LIVE TOOL
180 ppm = 10.5 gpg

Full converter with softener-sizing handoff →

Certification Reality Check

LIVE DATA
Six popular whole-house systems: what’s marketed vs what’s certified. Tap a column to sort.
System ↕ Flow GPM ↕ Certified claims ↕ Lead cert. ↕ 10-yr cost ↕
System A (carbon tank)12Chlorine, taste/odor✕ No$1,349
System B (catalytic)15Chlorine, chloramine✕ No$1,890
System C (cartridge)10Sediment, chlorine✕ No$2,140
System D (POE + POU)14Chlorine + lead at tap✓ NSF 53 (POU)$2,460
System E (carbon tank)9Taste/odor only✕ No$1,120
System F (iron/AIO)12Iron, sulfur (perf. data)✕ No$2,020
The pattern to notice: almost no whole-house system is lead-certified. Why — and what is →
SYMPTOM CHECK

What are you noticing?

Start with the symptom — each one has a short diagnostic before any product comes up.

Rotten egg smell Brown / orange water White residue & spots Metallic taste Cloudy or milky water Blue-green stains Black specks Sudden change in taste Low pressure after a filter
THE INDEX

The Contaminant Index, A–Z

Every entry links the sources, the health thresholds, the test that finds it, and the treatments that actually remove it — with certification receipts.

Browse the full index →
WHY TRUST US

How the Index earns trust

Review sites ask you to believe them. We built the site so you don’t have to.

✓

Every claim has a receipt

When we say a system is certified for lead, that claim links to the official NSF, WQA, or IAPMO database listing. Check us in one click.

✕

We list what it can’t do

Every product page carries a “does not remove” section and a “who should not buy this” verdict. The limits are part of the review.

?

Diagnosis before recommendation

Sometimes the answer is a $40 anode rod, a free utility test, or nothing at all. We publish those answers with no product attached.

Every fact on this site is labeled by its evidence type
Regulatory limit Health guideline Certified claim Manufacturer claim Editorial interpretation
THE LIBRARY

Guides & reviews by topic

The deep shelves of the index — start with a pillar, follow the links down.

Filtration 49 GUIDES

Hard water 30 GUIDES

Well water 28 GUIDES

Testing 20 GUIDES

CHANGE LOG

Recently verified

Every update is logged in public — re-checked prices, re-verified certifications, corrected errors.

Full update & corrections log →

Filters expire. Memories do too.

Get your system’s maintenance reminders and an annual re-test nudge. No deals, no daily emails.