Water testing · 7 min
How to read a water test report
Plain-English guide to lab units, guidelines, flags and what homeowners should send to an installer — without over-interpreting a single snapshot.
- Author
- WaterFilterHelp Editorial Team
- Canadian home-water research and consumer education
- Reviewed by
- WaterFilterHelp Standards Review
- Fact-checked against official Canadian guidance and certification sources
- Last reviewed
- 2026-08-23
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What to look at first
- Sample date, location (which tap) and lab accreditation notes
- Bacteria results (total coliform / E. coli) — presence matters immediately
- Each analyte’s result, unit (mg/L, µg/L, etc.) and the guideline or method reporting limit
- Any “exceeds” flags or comments from the lab
Common units
- mg/L (same as ppm for water) — hardness, iron, nitrates often appear here
- µg/L (ppb) — metals like lead and many PFAS results
- Grains per gallon — sometimes used for softener sizing; convert if your report is in mg/L as CaCO₃
Guidelines vs goals
Canadian drinking-water guidelines and provincial objectives are reference points — not DIY medical advice. Aesthetic objectives (staining, taste) can matter for treatment even when health guidelines are met.
Do not over-read one page
Seasonal changes, sampling mistakes and hold-time errors happen. Retest after floods or shocking a well. Keep prior PDFs so trends are visible.
What to send an installer
- Full PDF if possible
- Bacteria status
- Hardness, iron, manganese, pH, TDS
- Any PFAS, lead, arsenic or uranium numbers
- Smell/colour notes the lab cannot see
Paste highlights into our quote form, or use the WaterFilterHelp report interpreter to turn your numbers into plain English — then match a vetted pro when treatment is next.