Water · Commission the system · water-20

Run a baseline lab test before anyone drinks

Only a laboratory test tells you what is in your water. The baseline sets your treatment design and your benchmark for the future.

How

Use a laboratory certified for drinking water testing (US EPA). Local health departments may offer testing.
At minimum test total coliform bacteria, nitrates, total dissolved solids and pH, as CDC and US EPA recommend for private wells.
Ask your health or environmental department which local contaminants to add, such as arsenic, lead, radium, fluoride, VOCs or pesticides (CDC).
For rainwater, the Texas manual says test for pathogens before drinking.
Read your results against these key drinking water targets.
E. coli or faecal coliforms: 0 per 100 mL at the point of use (Sphere).
Turbidity: below 5 NTU (Sphere).
Free chlorine, if you chlorinate: 0.2 to 0.5 mg/L at the tap (Sphere); never above 5 mg/L (WHO guideline value).
Nitrate: 50 mg/L. Fluoride: 1.5 mg/L. Arsenic: 0.01 mg/L, a provisional value (WHO guideline values).
Your national standard may differ. Where it is stricter, use it.
Test after the treatment train too, to prove it works.
If a result exceeds a health standard, contact the health department and retest to confirm (US EPA).

Safety: Do not drink from a new source until results confirm it is safe. Use bottled or boiled water in the meantime.