A treatment proposal should trace back to a verified contaminant, concentration and target—not only taste, colour or a sales demonstration.
1. Confirm what was sampled
Record the well, tap, date, sampling point and whether treatment was bypassed. A sample before treatment answers a different question from one collected after a filter. Preserve laboratory instructions and chain-of-custody information.
If the result is unexpected, ask whether sampling, transport or recent plumbing work could have affected it. Do not use a home screening strip as a substitute for a certified laboratory result when health decisions depend on the number.
2. Read analyte, result, unit and detection limit together
The same numeric value can mean very different things in mg/L, µg/L or colony-forming units. “Not detected” usually means below a stated reporting limit, not proof that absolutely none is present.
Note qualifiers, method, detection limit and the laboratory’s comparison value. Keep the original report rather than copying only highlighted numbers into a quotation request.
3. Compare with current local health guidance
Private wells are not monitored like public supplies in many jurisdictions. CDC recommends at least annual testing for several basic indicators and asking local health authorities which additional hazards matter in the area.
CDC · Guidelines for testing well water ↗4. Match each treatment claim to evidence
List each confirmed problem, raw-water concentration, required treated-water target, peak flow and daily volume. Ask for independent performance documentation that covers the contaminant and conditions. No single treatment method removes every possible problem.
After installation, sample at the points needed to show whether treatment works. CDC advises testing treated water before drinking or using it after contamination. Plan ongoing monitoring and maintenance before purchasing equipment.
CDC · Guidelines for treating well water ↗Fields to copy from every laboratory result
| Field | Example question | Why it matters |
|---|---|---|
| Analyte | Exactly what was measured? | Defines the hazard or indicator |
| Result and unit | mg/L, µg/L or CFU? | Prevents scale errors |
| Reporting limit | How low could the method report? | Explains “not detected” |
| Sampling point | Before or after treatment? | Defines system condition |
| Date and method | Is the result current and suitable? | Supports comparison |
Worked example
Do not compare numbers without units
One report lists a contaminant in µg/L while an equipment sheet uses mg/L.
1 mg/L = 1,000 µg/L 25 µg/L = 0.025 mg/L
Convert units first, then compare the correct contaminant and treatment conditions. This conversion alone does not decide health significance.
What to have ready
- Original laboratory report
- Sampling point and treatment state
- Units, qualifiers and reporting limits
- Local health guidance and treatment performance evidence
Common mistakes
- Choosing equipment from taste alone.
- Treating “not detected” as absolute zero.
- Comparing mg/L directly with µg/L.
Reference check: 5 September 2026. Sources include US public agencies. Principles are general; regulations and design values must be checked where you live.Worked examples use stated hypothetical inputs.