If your home is on a private well, no agency tests your drinking water — the EPA's rules stop at public water systems. About 15 million U.S. households are their own water utility, and the entire quality-control department is you and a $50 lab test. Here's the testing schedule that public health agencies actually recommend, what it costs, and what to do with the results.
The testing schedule
| Test | How often | Typical cost | Why it matters |
|---|---|---|---|
| Total coliform bacteria | Every year | $20–$50 | The canary: indicates surface contamination is reaching your water |
| Nitrates | Every year | $15–$40 | From septic systems and fertilizer; dangerous to infants at levels you can't taste |
| pH, hardness, iron, manganese | Every 3 years | $40–$100 | Not health threats, but they destroy plumbing and water heaters |
| Arsenic | At least once, then every 3–5 yrs | $25–$60 | Naturally occurring in bedrock across much of the U.S.; tasteless, odorless |
| Lead | At least once (more if pre-1990 plumbing) | $25–$60 | Usually from your own pipes and fixtures, not the aquifer |
| VOCs / pesticides | If near industry, agriculture, or gas stations | $100–$400 | Site-specific risk |
| PFAS | Once, if near airports, military bases, or industry | $250–$500 | "Forever chemicals" — increasingly found in private wells |
Test immediately — regardless of schedule — when:
- The water changes in taste, smell, or color
- Your area floods, or your wellhead was submerged
- Anyone in the house has repeated GI illness
- You've had well work done, or the cap/casing was damaged
- A baby is joining the household (nitrate risk is highest for infants)
- You're buying the house — always, before closing, at the seller's expense if you can negotiate it
How to get a legitimate test
- Call your county health department first. Many offer free or subsidized bacteria/nitrate testing for residents, and all of them maintain lists of state-certified labs.
- Use a state-certified lab for anything health-related. Mail-in certified kits are fine; big-box store strips are screening toys.
- Sample correctly: use the lab's sterile bottle, take water from an inside tap (not a softener-treated or filtered one, unless testing the treatment), and follow the flame/alcohol sterilization instructions for bacteria samples exactly. Bad sampling is the #1 cause of false positives.
Reading your results
Your report will list each analyte against the EPA Maximum Contaminant Level (MCL) used for public systems — private wells aren't bound by them, but they're the health benchmarks that matter. Three outcomes:
- All below MCLs: file the report, retest on schedule. Keep every report — a documented water history adds real value when selling.
- Aesthetic issues (hardness, iron): treatment is optional and about protecting plumbing and appliances — softeners ($1,500–$4,000) and iron filters ($800–$3,000).
- Health exceedance (bacteria, nitrate, arsenic, lead): stop drinking the water, use bottled for cooking and drinking, and address the source. Common fixes: shock chlorination ($20 DIY, ~$150–$300 professional), UV disinfection ($400–$1,500 installed), reverse osmosis at the kitchen tap for arsenic/nitrate/lead ($300–$1,500).
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Frequently Asked Questions
How often should well water be tested?
At minimum: total coliform bacteria and nitrates every year, plus a full panel (metals, arsenic, lead, fluoride, hardness) every 3–5 years. Test immediately after flooding, any change in taste/odor/color, well repairs, or a new baby in the house (infants are most vulnerable to nitrates).
How much does well water testing cost?
A basic bacteria + nitrate test runs $30–$100 through your county health department or state-certified lab. A comprehensive panel covering metals, arsenic, and VOCs runs $150–$500. Many counties subsidize basic tests for residents — call your health department first.
Are home well-test strips reliable?
Strips are fine as a quick screen for hardness, pH, iron, and chlorine, but they cannot reliably detect bacteria, arsenic, or lead at health-relevant levels. Use a state-certified lab for anything you would make a health decision on. Strips say "look closer"; labs say "safe" or "not safe."
My well water tested positive for coliform — now what?
First, don't panic: total coliform indicates a pathway for contamination, not necessarily active disease risk (E. coli is the serious one). The standard response is shock chlorination of the well, retesting after 1–2 weeks, and if it returns, finding the entry point — commonly a cracked well cap, casing, or nearby septic issue. Persistent contamination usually means installing continuous disinfection (UV or chlorination).
Is well water safer than city water?
It's not safer or less safe by default — it's unregulated. City water is tested constantly under EPA rules; your well is tested exactly as often as you test it. Private wells serve about 15 million U.S. homes, and the EPA's Safe Drinking Water Act does not cover them. You are the regulator.