Well water, in plain English
What does your lab report say?
Pick the line that worries you. We’ll tell you what it means and what to do first.
Total coliform · Over the line: for one well, any positive counts
Coliform found: find the source, then retest.
Coliforms don’t occur naturally in groundwater, so find out how they got in. Shock chlorinate and retest. UV or continuous chlorination only if it keeps coming back.
What to do, step by stepE. coli · Over the line: act today
E. coli: don’t drink the water untreated.
Boil drinking water (at least 1 minute per Montana State; Texas says 2) and call your county health department today.
The next few daysNitrate · Over the line: 10 mg/L as N
Nitrate over 10 mg/L as N: call your county.
Wisconsin says pregnant women and babies under six months shouldn’t drink it, and don’t use it for formula. Check the unit first: 10 mg/L as N is about 44 to 45 mg/L as nitrate. Boiling raises nitrate.
Read the nitrate lineArsenic · Over the line: 10 µg/L (0.010 mg/L)
Arsenic over 10 µg/L: ask which form you have.
Call your county. Ask the lab for As(III) and As(V): adsorptive media handle both, reverse osmosis needs pre-oxidation for As(III).
Read the arsenic lineIron or manganese · Not a health limit
Stains are a treatment question, not a health limit.
Iron above 0.3 mg/L leaves rust-colored stains, manganese above 0.05 mg/L black ones. The iron filter goes before the softener; UV, if you need it, goes last.
Put the filters in orderNo report yet · Start here
Start with four tests, once a year.
Total coliform, nitrate, pH and TDS. The EPA and the CDC agree on that list. At the Penn State lab the set costs $70; the full move-in panel $220.
What to test forNo report, but the septic acts up? Start with the warning signs or see when the tank is due.
Out here, no agency tests your well for you.
More than 43 million Americans drink from a private well. The EPA’s limits are written for public water systems; for your well they’re a yardstick, not a rule. The water, the tank and the field are yours to look after.
Read these three lines first
Bacteria, nitrate and arsenic carry health limits and turn up in private wells. Then check the unit on every line before you compare it with a limit.
1 in 5In a USGS study of 2,100 private wells, about one in five had at least one contaminant above a health benchmark.
| Line | Result | Limit | Status |
|---|---|---|---|
| Total coliform | Present | Absent | Retest |
| E. coli | Absent | Absent | OK |
| Nitrate (NO3) | 31 | 45 | OK |
| Arsenic | 0.012 | 0.010 | Over |
The trap on this report: nitrate is reported as NO3, so the limit is 45, not 10. Compare against the wrong one and a safe 31 looks three times over.
Thirty years on a well and septic, to scale
Two habits do most of the work: a yearly well test and a tank that gets pumped on time. The big bills sit further out.
Or start from where you are
- Reading Your ResultsHow to Read Your Well Water Test Results, Line by Line
Which three lines to read first, what every EPA number means for a private well, a table of 25 report lines, and five common misreadings.
16 min read - Testing Your WellHow Often to Test Well Water, and What to Test For
Test every year for bacteria, nitrate, pH and TDS, then add tests for where you live. A situation table, three test levels and real lab prices.
13 min read - Treating Your WaterWell Water Treatment Order: What Goes First, and Why
Sediment, pH, iron and sulfur, softener, then carbon or RO, UV last. The number that decides each step, four example wells, and what RO does to a septic.
15 min read - Septic CareHow to Maintain a Septic System: The 30-Year Routine
Inspect every 1 to 3 years, pump by tank size and household, don't send more water than a normal household. A 30-year calendar and EPA pump-out numbers.
12 min read - Septic Problems & RepairSigns of a Failing Septic System, and What to Do First
Backups, slow drains, wet spots, lush grass: what each sign points to (pipe, tank or field), what to do this week, and what repair usually costs.
13 min read - Buying & OwningBuying a House With a Well and Septic: What to Check
A three-stage checklist: questions before the offer, a lab water test and a real septic inspection during the contingency, and what each check costs.
13 min read