City water gets tested hundreds of times a month by law. Your well gets tested exactly as often as you decide to test it — which, for the average private well owner, is once: the day the house was bought. Surveys by state health departments routinely find that fewer than half of well owners have tested in the past year, and most can't locate their last result.
The fix isn't complicated. Well testing runs on a simple three-tier schedule — every year, every 3–5 years, and after specific events. Here's the whole thing.
Tier 1: Every Year, No Exceptions
Two tests, once a year, ideally in spring (after snowmelt and rain have stressed the system — the most likely time to catch a problem):
- Total coliform bacteria & E. coli — the canary for surface contamination. What a positive means.
- Nitrates — mobile, seasonal, and dangerous to infants. The full nitrate picture.
Add to the annual list if they apply to you:
- Anyone pregnant or an infant in the house → make nitrate non-negotiable and consider a second test in late summer.
- You have treatment equipment (RO, arsenic media, UV, softener) → test the treated water annually to prove the equipment still works.
An annual kit like the Tap Score Essential Well Water Test covers bacteria, nitrates, and the core chemistry in one mail-in box — order the same kit every year and your results are directly comparable, which is the whole point.
Tier 2: Every 3–5 Years (and Once, Ever, for Every Well)
The broader panel — because slow-moving chemistry doesn't change month to month, but it does change:
- pH, hardness, iron, manganese, sulfate, total dissolved solids — the "aesthetic" panel that predicts staining, scaling, and pipe corrosion before you see them.
- Arsenic — naturally occurring, no pollution needed. Every well must test at least once; retest every 3–5 years in hotspot regions.
- Lead — if your home predates 1988, test at the tap, not the well; the source is usually the plumbing.
- Regional extras: radon and uranium in granite country (New England, Rockies); VOCs near gas stations, dry cleaners, or industry; PFAS near airports, military bases, or firefighting training sites; pesticides in row-crop country.
If you have never run a comprehensive panel, do it this year in place of the basic kit — you need the baseline once before the cheap annual cadence means anything.
Tier 3: Test Right Now If…
Events beat calendars. Any of these triggers an immediate bacteria test (plus whatever the event suggests):
- Flooding at or near the wellhead — full flood protocol here.
- Any work on the well or pump — every time the system is opened, test after.
- Change in taste, smell, or appearance — new cloudiness, sulfur smell, orange staining.
- Unexplained GI illness in the household, especially in guests (residents build tolerance to their own water's flora).
- A new septic system, livestock operation, or drilling near your property.
- Buying a house with a well — the one time to run the full everything panel. The 12-point checklist.
Why This Schedule Fails (and How to Make It Stick)
Nobody forgets to test because testing is hard — a mail-in kit takes ten minutes. It fails because there is no system: no reminder, no record of the last result, no baseline to compare against. The result from three years ago is in a landfill or an email you can't find, so even when you do retest, the number floats free of context. Was iron always 0.4? Is nitrate climbing?
This is precisely the job the WellKept app was built for. Snap a photo of each lab report, log the headline numbers, and WellKept keeps the trend line. Set the annual test as a recurring reminder and spring testing stops depending on your memory. When you sell the house, hand the buyer a complete testing history — the rarest and most trust-building document a well owner can produce.
Your action plan: (1) If it's been over a year — or ever — since your last test, order the annual kit today. (2) Never run the comprehensive panel? Run it once this year. (3) Log the results and set next spring's reminder in WellKept. Done: your well now has a monitoring program.
Frequently Asked Questions
How often should a private well be tested? Test every year for total coliform bacteria and nitrates, every 3–5 years for the broader chemistry panel (pH, hardness, iron, manganese, arsenic, lead, TDS), and immediately after floods, well repairs, or any change in taste, smell, or appearance. Spring is the best annual timing.
What should I test my well water for? Annually: bacteria and nitrate. At least once ever, and periodically after: arsenic, lead, pH, hardness, iron, manganese, and total dissolved solids — plus regional risks like radon, uranium, VOCs, PFAS, or pesticides depending on your geology and neighbors.
How much does it cost to test well water? Basic annual bacteria + nitrate testing runs $30–$80 through a mail-in lab kit or your county health department (some offer free or subsidized bacteria tests). A comprehensive panel covering metals, minerals, and organics runs $150–$300 — worth it once for a baseline and when buying a home.
Can I test well water myself? Home test strips exist for hardness, pH, iron, and chlorine and are fine for screening aesthetics. For anything with health stakes — bacteria, nitrate, arsenic, lead — use a certified laboratory, because strips lack the sensitivity to detect these at the concentrations that matter.
What is the best time of year to test well water? Spring, after snowmelt and heavy rains — that's when surface contamination is most likely to reach a well, so a clean spring test is the most reassuring result. In agricultural areas, add a late-summer nitrate check to catch post-fertilizer peaks.