Aqua Otter
Aqua Otter Library

Know your
water.

Deep guides on contaminants, treatment science, and local water conditions. Written by people who test water for a living.

Featured Guides

Contaminants8 min read

Chromium-6 in Indiana's Water Supply

Chromium-6 appears in CCR reports across Hamilton, Marion, and Allen counties. Here's what it is, where it comes from, and what actually removes it.

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Contaminants9 min read

PFAS Contamination in Michigan: What Homeowners Need to Know

Michigan has documented PFAS contamination at hundreds of sites. Here's the science, the affected areas, and what filter technologies actually work.

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All Guides

Science7 min read

How Ion Exchange Softening Works

The science behind salt-based water softeners: what they remove, how the resin bed works, what regeneration does, and what softeners don't do.

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Contaminants7 min read

TTHMs and Haloacetic Acids: The Disinfection Byproducts in Your Tap Water

Municipal water treatment creates its own contaminants. Here's what TTHMs and HAA5 are, why they form, and what actually removes them.

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Science6 min read

Water Hardness Explained: GPG, TDS, and What It Means for Your Home

What hardness actually measures, how GPG and TDS differ, where Indiana and Michigan cities rank, and what happens at each hardness level.

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Systems8 min read

Salt-Based Softener vs. No-Salt Conditioning: An Honest Comparison

Both systems treat hard water but they work completely differently. Here's when each one is right, and the marketing claims you should ignore.

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Systems7 min read

Whole-Home Filtration: What It Covers, What It Doesn't, and How to Choose

A point-of-entry filtration system treats water before it reaches any tap. Here's what different whole-home systems target and how to match the system to your water.

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Looking for specific water terms?

The Aqua Otter Glossary defines every term in plain English.

View Glossary Free Water Test