WaterAnswer.com

Water quality involves a lot of acronyms and overlapping standards. EPA limits, NSF certifications, and utility reports all measure different things in different ways.

The guides here translate those systems into plain language. No jargon. Just what you need to make a good decision.

Start with your water quality report if you have city water — your utility sends one every year and most people never read it. If you have a private well, start with the EPA and NSF explainers, which will help you understand what your test results mean and what certification to look for in treatment equipment.

Reference Guides

How to Read Your Water Quality Report

Your utility sends a Consumer Confidence Report every year. Most people don't know what's in it. Here's how to read it.

EPA MCL vs. MCLG: What the Difference Means

Legal limits and health-based limits are different numbers. Understanding why matters when you read contamination test results.

NSF Certification Standards Explained

NSF 42, 53, 58, 401 — what each certification actually covers and why it matters when choosing a water filter.

Frequently Asked Questions

What is a Consumer Confidence Report?
A Consumer Confidence Report (CCR) is an annual water quality report that public water utilities in the US are required to send to customers. It lists the contaminants tested, their measured levels, and the EPA limits that apply. Private well owners don't receive CCRs — they're responsible for testing their own water.
What does EPA MCL mean?
MCL stands for Maximum Contaminant Level — the highest amount of a contaminant that is legally allowed in public drinking water. MCLs are set through a regulatory process that weighs health risk against what treatment technology can reliably achieve and what it costs. They are not the same as health-based limits.
What is NSF certification for water filters?
NSF International is an independent testing organization that certifies water treatment products. Different NSF standards cover different contaminants. NSF 42 covers taste and odor. NSF 53 covers health-effect contaminants like lead. NSF 58 covers reverse osmosis systems. A filter certified under one standard is not automatically certified under others.