Our methodology

How Home Water Compass decides what to recommend — and what it refuses to guess.

Diagnose the decision before any recommendation

Every recommendation starts from your water source, what you've noticed, and what evidence actually exists. We separate three levels of evidence and never blend them into a single score: information reported by your utility, symptoms you describe, and results from a qualifying laboratory test.

What ranks a recommendation

• Official public-health guidance always comes before any commercial suggestion.
• If evidence is insufficient to choose treatment, we recommend testing first.
• Products must carry an exact, model-level certified claim for your concern.
• Fit — source, scope, evidence, your preferences — always outranks compensation.

What we will not do

We do not produce safety scores, diagnose a cause from a symptom alone, or present area-level utility data as a test of your tap. When we don't know something, the report says so.