Well Water Testing: What to Test For and How Often
If your home is on a private well, no one tests your water but you. Here's exactly what to test for, how often, and what the results mean for your family's health.
If your home draws from a private well, you are your own water utility — which means no one tests your drinking water but you. Well water can look crystal clear and taste fine while carrying bacteria, nitrates, or heavy metals you'd never detect by sight. Testing is the only way to know it's safe, and it's a simple yearly habit.
Why it matters
City water is tested constantly and held to EPA standards. A private well has none of that oversight. Contamination can arrive from septic systems, farm runoff, road salt, flooding, or the natural geology of your area — often with no change in taste or smell. The risks are real: bacteria cause acute illness, and nitrates are especially dangerous to infants. Annual testing is cheap insurance against problems you literally cannot see.
What to test for
Every year (the essentials):
- Total coliform bacteria, including E. coli — indicators of contamination from surface water or septic.
- Nitrates — from fertilizer, septic, and animal waste; dangerous to infants.
Periodically (every few years, or based on your area):
- Lead and heavy metals (arsenic, manganese), which leach from geology or old plumbing — especially galvanized pipe.
- pH and hardness — affect corrosion, scale, and how your fixtures and water heater hold up.
- Local concerns — radon, uranium, or pesticides, depending on geology and agriculture nearby.
Test immediately any time the water changes in taste, color, or smell, after flooding, or after any well repair.
How to test it right
The result is only as good as the sample:
- Use a certified lab or your health department's kit — not a hardware-store test strip. Many local health departments provide free or low-cost bacteria kits.
- Collect the sample exactly as instructed — usually running a cold tap a few minutes, then filling a sterile container without touching the opening.
- Get bacteria samples to the lab fast and cold — often within 24–30 hours — or the results are meaningless.
- Compare results to EPA limits the lab provides.
Owner Tools tracks this as test well water quality.
What the results mean
- Bacteria present: stop drinking it. Shock-chlorinate the well (disinfect it), then retest. Recurring bacteria means find the source — often a cracked well cap, shallow casing, or nearby septic issue.
- High nitrates: don't give the water to infants; treatment (reverse osmosis or ion exchange) or an alternate source is needed.
- Hard water or metals: a softener or specific filtration system addresses these; they're comfort-and-longevity issues more than acute health ones (except lead and arsenic, which are serious).
Don't forget the equipment
A well is a system, not just water. Check the well pressure tank — a waterlogged tank short-cycles the pump and burns it out early. Inspect the well cap for cracks or gaps that let contaminants in. When the pump or tank is aging, know the signs it's time to replace.
Make it automatic
Build your free Owner Tools plan and we'll schedule the annual water test and pressure-tank check at the right time of year for your well. No login, no address required. Start from the well water overview.