How the checkup decides

The checkup is a transparent rules engine. Every recommendation it can produce is listed below with its trigger and its authority. It never uses your answers for anything except rendering your result in your browser — see Privacy.

If…The checkup says…Authority
You have a private well (always)Bacteria + nitrate/nitrite every yearMaine CDC, Well Water testing recommendations
No full panel in 3–5+ years (or never/unknown)Arsenic, uranium, radon, lead, manganese, fluoride, pH and related panel dueMaine CDC (3–5 year list)
Flooding, well/pump work, or a change in taste, odor, color, stainingRetest bacteria + nitrates nowMaine CDC / US EPA event-trigger guidance
Buying with FHA financingColiform, nitrate, nitrite, lead testHUD Handbook 4000.1 (individual water systems)
Buying with VA/USDA financingWell test satisfying the local health authority (bacteria + nitrate/nitrite floor, commonly lead)VA / USDA program requirements
SellingMaine sellers disclose the date of the last water test33 M.R.S. §173
Rental property on a wellArsenic test at least every 5 years; share results with tenants22 M.R.S. §2660-Y
Infant under 1 / pregnancy in householdDo not defer the nitrate testMaine CDC / US EPA (methemoglobinemia risk)
Near historic sludge/septage spreadingPFAS testing is a consideration; see Maine DEP mapMaine DEP PFAS investigation
Coastal wellInclude chloride/sodium next panelMaine CDC (saltwater intrusion)

Status logic: any overdue or event-triggered item → Testing is due now; items inside their window → coming due; otherwise on schedule. "I don't know" is always treated as due — the conservative reading.

Full citations with URLs and access dates: Sources. Limitations of area-level data: Disclaimer.