Post-installation water-treatment verification checklist

Before installation

Keep the accredited raw-water report used for system design. Record the sample point, date, units, detection limits and operating conditions. Confirm each proposed device has the exact certification claim needed for the target contaminant.

Commissioning day

Have the installer flush and sanitize the system according to the manufacturer’s instructions. Record model and serial numbers, media, flow settings, pressure, bypass position and the maintenance schedule.

Initial verification

After the specified flush or conditioning period, use an accredited laboratory to collect paired raw and treated samples for the target health-related contaminants. Use the same units and comparable analytical method. A handheld TDS meter can help monitor an RO trend but cannot prove removal of PFAS, lead, arsenic, uranium or microorganisms.

UV systems on private wells

Test for total coliforms and E. coli after commissioning and after corrective work. UV performance also depends on pretreatment, UV transmittance, flow, lamp age and a clean quartz sleeve. A lighted lamp is not proof of disinfection.

Ongoing verification

Retest on the schedule advised by your public-health authority and whenever water changes, flooding or well work occurs, equipment alarms, media is exhausted, or treatment is serviced. Keep results with maintenance records so trends are visible.