Editorial policy & methodology

Sources we rely on

• Regulators: U.S. EPA (Safe Drinking Water Act rules, Consumer Confidence Reports), Health Canada Guidelines for Canadian Drinking Water Quality, state and provincial drinking water programs.
• Science agencies: USGS (water hardness, PFAS studies), CDC (boil-water and well guidance).
• Utilities' own annual water quality reports and public notices.
• Certification standards: NSF/ANSI 42, 44, 53, 55, 58, 401 and certifier listings.

City profiles

Each profile names the utility and its source water and gives a typical hardness band on the USGS scale. We use bands rather than single numbers because hardness varies by plant, blend and season. Profiles are not safety ratings. We link to the official report so readers can check current results.

Keeping things current

Regulatory figures are reviewed whenever rules change and at least twice a year. Each guide shows its last-updated date. The news page refreshes automatically every day from public feeds.

Corrections

Found an error? Tell us. We fix factual errors promptly and note substantive corrections in the article.

Independence

We don't sell water products. Advertisers and sponsors cannot buy editorial conclusions, rankings or safety statements, and sponsored material is labelled. We only recommend technologies by certification standard, never by brand payment.

Use of AI

We use software tools — including AI writing assistants — to help research, draft and check content. Every published guide is reviewed by a human editor against the primary sources above.