Well Water Test Interpreter
Enter your lab results — or upload your lab report and we’ll read it for you — and get a plain-English verdict on every parameter: what’s fine, what to watch, and what needs treatment. Benchmarked against EPA’s public-water-system standards, the best yardstick private wells have.
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Honest limits
- Not medical or lab advice. This tool benchmarks your results against EPA’s public-water-system standards. It’s a starting point for a conversation with your lab or a water-treatment pro — not a diagnosis.
- Infants and pregnancy. This tool never clears water as safe for infant formula — not even when every number passes. Nitrate over 10 mg/L as N can cause blue-baby syndrome in infants under 6 months, and no website can rule out a sampling or lab error. If an infant under 6 months drinks this water: have a certified lab confirm nitrate and nitrite, talk to your pediatrician, and use bottled water for formula until then. Pregnant? Same caution — ask your doctor.
- PDF reading is beta. Lab report layouts vary wildly. Every number we pull from your PDF is shown back to you with the exact line it came from — check each one before we interpret anything. Parsed values are suggestions, never trusted silently.
- Private wells aren’t regulated. EPA’s limits legally apply to public water systems. For private wells they’re the best available yardstick — which is how we use them here.
- Detection limits. A “<” means your lab couldn’t see below that number. If that number sits above our OK line, we mark it “can’t judge” instead of guessing.
- Nitrate basis. Labs report nitrate two ways — “as nitrogen” or “as nitrate.” We convert automatically, but if your report doesn’t say which, double-check the number we used.
- Lead. EPA lowered the lead action level to 10 ppb (0.010 mg/L) in 2024. Older reports and articles may still say 15 ppb.
- Bacteria. A “present” coliform result means retest first to confirm, then act. Sampling mistakes cause false positives — that’s normal, not a failure.
Want the full explanation behind every line on your report? Read how to read your well water test results.
Benchmarks: the exact lines behind every verdict
Every pass/fail line in this tool traces to a U.S. EPA or CDC primary document — nothing from filter-vendor blogs. Aesthetic (secondary) standards are never presented as health failures. Hardness has no EPA standard, so it’s shown for context only, using the USGS classes.
| Parameter | Benchmark we use | Source |
|---|---|---|
| pH | 6.5–8.5 (aesthetic) | EPA Secondary Drinking Water Standards |
| Hardness | No EPA standard — USGS classes shown for context (0–60 soft, 61–120 moderately hard, 121–180 hard, >180 very hard) | USGS Water Science School: Hardness of Water |
| Iron | 0.3 mg/L (aesthetic) | EPA Secondary Drinking Water Standards |
| Manganese | 0.05 mg/L (aesthetic); 0.3 mg/L lifetime health advisory (2004) | EPA Secondary Standards; EPA Drinking Water Health Advisory for Manganese (2004) |
| Nitrate | 10 mg/L as N — 45 mg/L as NO3 (health) | EPA National Primary Drinking Water Regulations (MCL table) |
| Nitrite | 1 mg/L as N — 3.3 mg/L as NO2 (health) | EPA National Primary Drinking Water Regulations (MCL table) |
| Total dissolved solids (TDS) | 500 mg/L (aesthetic) | EPA Secondary Drinking Water Standards |
| Total coliform | Indicator test — presence means retest, not a violation | CDC Guidelines for Testing Well Water |
| E. coli | Health goal: zero — any detection means act | EPA National Primary Drinking Water Regulations (MCLG: zero) |
| Arsenic | 0.010 mg/L — 10 ppb (health) | EPA National Primary Drinking Water Regulations (MCL table) |
| Lead | 0.010 mg/L — 10 ppb action level (2024 Lead and Copper Rule Improvements) | EPA Lead and Copper Rule Improvements fact sheet (Oct 2024) |
| Sodium | 20 mg/L advisory for very-low-sodium diets; 30–60 mg/L taste threshold | EPA Drinking Water Advisory: Sodium (2003) |
| Chloride | 250 mg/L (aesthetic) | EPA Secondary Drinking Water Standards |
| Sulfate | 250 mg/L (aesthetic) | EPA Secondary Drinking Water Standards |
| Fluoride | 4.0 mg/L (health); 2.0 mg/L (cosmetic — tooth discoloration in children) | EPA National Primary Drinking Water Regulations; EPA Secondary Standards |
| Copper | 1.3 mg/L action level (health); 1.0 mg/L (aesthetic) | EPA National Primary Drinking Water Regulations (action level); EPA Secondary Standards |
| Zinc | 5 mg/L (aesthetic) | EPA Secondary Drinking Water Standards |