Nobody Tests Your Well But You. Here's What to Test For and How Often.

If you get your water from a city or county utility, you get a Consumer Confidence Report once a year whether you ask for it or not — someone else tested the water and mailed you the results. If you get your water from a private well, nobody does that for you. No agency tests it, no report shows up in your inbox, and the well itself gives you almost no warning when something's wrong. Most contaminants that matter don't have a taste, smell, or color. The only way you find out is if you test. The four things to test every year, no matter where you live. The Centers for Disease Control and Prevention recommends testing private wells at least once a year for four things: total coliform bacteria, nitrates, pH, and total dissolved solids (TDS). Coliform bacteria is a family of bacteria used as an indicator — most types aren't harmful themselves, but their presence means something (usually surface water or septic runoff) is getting into your well that shouldn't be, and it's a flag to look closer for the kind that are harmful. Nitrates are a byproduct of fertilizer, manure, and septic systems soaking into groundwater; at high levels they're a specific risk for infants, which is why "nitrates" shows up on nearly every well-safety checklist aimed at new parents. pH just measures how acidic or basic your water is, which affects both taste and how much your plumbing corrodes over time. TDS is the total amount of dissolved minerals and salts in the water — not dangerous at typical levels, but a rising number over the years can be an early sign that something near your well has changed. None of these four requires a specialty lab. A basic well-water panel from any state-certified laboratory covers all four for a reasonable price, and your state or local health department can point you to one — this matters because a lab that isn't certified for drinking water testing can hand you numbers that don't hold up if you ever need them for anything official. What pushes you to test sooner, or test for more. The annual panel is the baseline, not the ceiling. Both the CDC and EPA list specific situations that call for testing right away, outside the yearly schedule: flooding or heavy land disturbance anywhere near the well, any repair or replacement of well components, a noticeable change in your water's taste, color, or smell, or a new baby or pregnancy in the house. That last one isn't boilerplate caution — nitrate exposure is a genuine, well-documented risk for infants under six months, so it's worth a fresh nitrate test specifically, not just an assumption that last year's result still holds. Beyond the core four, what else you should test for depends heavily on where you live, and this is the part homeowners tend to skip because it isn't automatic like the annual panel. The EPA's own guidance ties specific contaminants to specific situations: wells near agricultural land are worth testing for pesticides in addition to nitrates and coliform; wells near current or former industrial sites for volatile organic compounds (VOCs) and metals; older homes with older plumbing for lead and copper, since those come from your own pipes rather than the aquifer. Radon and arsenic are regional — both occur naturally in groundwater in specific geology, so whether they're worth testing for depends entirely on what's normal in your area. Your local health department knows this local baseline better than any national guide can, and asking them "what does everyone around here test for besides the basics" is a genuinely useful five-minute phone call. Reading the result without a CCR to compare it to. A municipal report comes with a built-in comparison: your utility's numbers get measured against the EPA's Maximum Contaminant Level (MCL) for each substance, and the report tells you where you stand. A private well test usually comes back as a plain list of numbers with no context, because there's no MCL enforcement mechanism for private wells at all — that's a legal fact, not an oversight, and it's the reason all of this testing is on you in the first place. Most certified labs will flag a result that exceeds the EPA's health-based guidance even though nothing requires them to, but it's worth asking specifically whether your lab does that, or whether you're expected to compare the numbers yourself. If a result comes back high on anything, that's a conversation with the lab or your health department about next steps — retesting to confirm, narrowing down a source, or looking at treatment options — rather than something to sit with for another twelve months. A well that tested clean last year isn't a guarantee about this year; it's just this year's job not done yet. Primary references: CDC – Guidelines for Testing Well Water EPA – Protect Your Home's Water