Turn measurements into better questions.
Enter only what was actually tested. A blank means untested; a zero is a reported measurement. For “not detected,” keep the laboratory’s detection limit in your original report instead of entering zero.
No values are uploaded or stored. Download a copy before leaving this page.
Numbers need context
Identify the sample point, method and collection date before comparing readings. Untreated water answers a different question from water collected after a filter. A meter, test strip and laboratory report can have different uncertainty and reporting limits.
Hardness conversion and classification
One grain per US gallon is approximately 17.1 mg/L as calcium carbonate. The tool uses the USGS bands: soft through 60 mg/L, moderately hard above 60 through 120, hard above 120 through 180, and very hard above 180. These describe mineral hardness, not potability.
Aesthetic guidelines are not health clearances
EPA secondary reference values include iron 0.3 mg/L, manganese 0.05 mg/L, TDS 500 mg/L and pH 6.5–8.5. Manganese also has health-related considerations. Use a certified laboratory and relevant health guidance for a drinking-water concern; do not use an aesthetic comparison as a safe limit.
Free chlorine, total chlorine and test timing
Free and total chlorine are different measurements. Total includes free and combined chlorine. Use the correct method and prompt sample testing; a zero free reading does not prove that no disinfectant or no germs are present.
Keep the original report
A downloadable profile is a record of your entries and educational interpretation. Preserve the laboratory report, sample instructions and detection limits. For private wells, maintain a separate bacteria and nitrate testing plan.
Sources & further reading
Primary references for this guide. Confirm current requirements and notices with the responsible authority.
General information helps you prepare. Actual conditions, equipment instructions and the responsible authority determine the work at your property.