Well Water Test Schedule Calculator
Last test date to next due date and yearly panel.
What it does
Private wells answer to no utility: the owner tests, treats, and tracks. Yearly bacteria, nitrate, and pH screens catch most trouble early, and the calendar is simply last test plus twelve months.
The tool above adds 365 days to the last lab date in UTC and prints the next due date with the standard yearly panel. Floods, new pumps, and funny tastes override it with immediate retests.
EPA private-well pages put testing on owners with yearly bacteria and nitrate screens, and USGS well-water studies back the habit with contamination data. State labs supply bottles, menus, and fees behind the schedule.
Test on time and file everything. One positive needs shock chlorination plus a confirm; patterns need source work on casing, caps, and nearby land. Treatment follows test results, never guesses.
How to use
- Enter the last lab test date.
- Read the next due date.
- Read the yearly panel list.
- Order state-lab bottles ahead.
- Retest early after floods or work.
- File every report with the house.
Formula
- last test
- Date of the last lab test.
Annual cadence follows EPA private-well guidance with state variations. Dates compute in UTC at noon to dodge daylight-saving shifts. Floods, new equipment, and sensory changes override the calendar with immediate retests.
Worked example
Example: tested Jan 15, 2026
Private well last tested January 15, 2026.
- Last test was Jan 15, 2026.
- Wells test every 12 months.
- Next due: Jan 15, 2026 + 365 = Fri Jan 15 2027.
- Panel: bacteria, nitrate, pH yearly.
- Retest sooner after floods or nearby work.
Reference table
| Situation | When | Panel |
|---|---|---|
| Routine year | Every 12 months | Bacteria, nitrate, pH |
| After floods | Immediately | Bacteria plus local extras |
| New pump or work | After flushing | Bacteria, nitrate |
| Taste or odor change | Now | Full local menu |
| Home sale | Per contract | Buyer and lender panel |
Limits
- Schedule only. Labs interpret results.
- Annual panel; local extras vary.
- UTC date math; confirm leap quirks with the lab.
- Treatment needs its own diagnosis.
Common mistakes
- Never testing a clear-tasting well.
- Using strips instead of certified labs.
- Skipping retests after floods.
- Testing without a plan for positives.
- Losing old reports before sale.
Try it yourself
Quick checks. Answers sit tucked under each question.
Last tested Jun 1, 2025?
Next due is Jun 1, 2025 + 365 = Mon Jun 01 2026. Panel: bacteria, nitrate, pH.
Last tested Oct 16, 2025, then flooded?
Next due is Oct 16, 2025 + 365 = Fri Oct 16 2026. Floods override: retest now.
Questions
How often should wells test?
Yearly for bacteria, nitrate, and pH, plus any local extras. Floods, nearby spills, new pumps, or taste changes reset the clock immediately.
What does the yearly panel cover?
Total coliform and E. coli, nitrate, and pH every year; lead, arsenic, radon, and minerals on local schedules. State labs publish the menu with bottles and fees.
Does anyone test my well for me?
No. Cities test to federal standards; private wells are the owner's job in most states. EPA and state programs publish guidance, not lab orders.
Home strip or certified lab?
Use a state-certified lab with its own bottles and holding times. Home strips screen; labs decide. Keep every report with the house file.
What if bacteria shows up?
Shock-chlorinate per state guidance, flush to clear, then retest to confirm. Repeat positives need the source: casing, cap, or nearby contamination.
Do I need treatment too?
Test first, treat to the result: softeners for hardness, neutralizers for acid water, certified filters for specific contaminants. Treating blind wastes money.