Public water systems are tested constantly. Private wells aren't, unless you do it. Owners are responsible for their own water quality, and testing is the only way to know what's in it.
What the EPA recommends
The EPA recommends testing private wells at least once a year for total coliform bacteria, nitrates, total dissolved solids and pH, and more often or for more contaminants if there's a reason to suspect a problem. Test after any flood, when the well has been worked on, if the taste, color or smell changes, if someone in the household is pregnant or nursing, or if there are infants in the home.
Core tests
- Total coliform and E. coli. Indicators of bacterial contamination from surface water, septic systems or animals. Any E. coli is a problem.
- Nitrate. The EPA drinking water standard for nitrate is 10 mg/L (as nitrogen). High nitrate is especially dangerous for infants. Sources include fertilizer, manure and septic systems.
- pH, hardness, iron and manganese. Mostly aesthetic and plumbing issues (staining, scale), but they determine what treatment you need.
- Other contaminants. Depending on local geology and land use, arsenic, uranium, radon in water, lead (from plumbing), sodium or chloride (road salt), and organic chemicals may be worth testing. Your county health department and a state-certified lab can recommend local tests; road salt (sodium and chloride) is worth checking for wells near roads.
How to sample
Use a state-certified laboratory and follow its bottle and sampling instructions exactly. Bacteria samples have short holding times, so they often have to reach the lab within a day. Remove aerators, run the water, and don't sample right after a shock chlorination.
If results come back bad
- Coliform positive: shock-chlorinate the well, flush, and retest. Repeated positives point to a construction problem (cracked casing, bad cap, poor grout seal, wellhead in a low spot) that a well contractor should inspect.
- High nitrate: don't use the water for infant formula. Options include reverse osmosis or ion exchange treatment, or a deeper, better-sealed well.
- Iron, manganese, hardness: softeners and oxidizing filters are common fixes.
- Arsenic, uranium and others: specialized treatment, often point-of-use reverse osmosis. Retest after installing treatment.
Testing when buying a home
If you're buying a house with a well, test before closing: bacteria and nitrate at minimum, plus a flow test to see whether the well can keep up with the household. Ask for the well's completion report if the seller has it.
Protect the wellhead
Keep the casing at least a foot above ground, with a tight sanitary cap. Slope soil away from it. Keep fertilizer, pesticides, fuel and animals away. Have the septic system pumped and inspected on schedule.
Shock chlorination
When bacteria show up, the standard first step is shock chlorination: introducing a strong chlorine solution into the well and plumbing, letting it sit for a period recommended by your state or extension service, then flushing until the chlorine is gone and retesting. Run the flushed water somewhere it won't harm a septic system, lawn or stream. If bacteria come back, the cause is usually a physical problem with the well that chlorine can't fix.
Choosing treatment
Match the treatment to the test result, not to a sales pitch. Water softeners address hardness. Oxidizing filters handle iron, manganese and hydrogen sulfide (rotten-egg smell). UV disinfection treats bacteria in otherwise clear water. Reverse osmosis at the kitchen sink reduces nitrate, arsenic and many dissolved contaminants for drinking and cooking. Whole-house systems need maintenance. Filters need changing and UV lamps need replacing, so factor that into the decision. Retest after any treatment is installed.
Keeping records
Keep every lab report in one place with the date. Trends over time, such as rising nitrate or chloride, tell you more than a single test and can show when something nearby has changed.
Understanding a lab report
Lab reports list each contaminant, the result, the units (often mg/L, which is the same as parts per million, or µg/L, parts per billion), and a comparison value. For contaminants with an EPA maximum contaminant level (MCL), the report usually shows it. Nitrate, for example, is reported against the 10 mg/L (as nitrogen) standard. Secondary standards cover taste, odor and staining issues like iron and manganese; those aren't health limits but explain why water stains fixtures or tastes off. Bacteria results usually read "present" or "absent." If anything is unclear, ask the lab or your county health department to walk through it with you.
Seasonal changes
Water quality in a well can change with the seasons. Bacteria problems often show up after heavy rain or snowmelt, when surface water moves quickly into the ground. Nitrate can rise after fertilizer application. If you test only once a year, vary the season occasionally, or test after big storms.
Neighbors and land use
What's around your well matters. Septic systems, livestock, fuel storage, road salt, old dumps and nearby agriculture all affect what you should test for. If several neighbors share similar problems, it may point to a local source, and your health department will want to know.
Before you call a contractor: a checklist
- Address or parcel and whether public water is available.
- What the water is for. House, irrigation, livestock or all of them.
- Existing well details if you have one: depth, age, pump age and any records.
- Symptoms for repairs: no water, low pressure, short cycling, air, sediment, taste or smell.
- Septic location, so the new well can meet separation distances.
- Access for a drill rig (they're large trucks) and the distance to the house.
- Neighbors' well depths if you know them.
- Timeline, including any closing or construction deadline.
The more a contractor knows up front, the more accurate the first estimate.
Serving Dutchess County and nearby
We take requests from property owners across Dutchess County and the mid-Hudson Valley, including Poughkeepsie, Hopewell Junction, Red Hook, Rhinebeck, Poughquag (Beekman), Clinton Corners, Millbrook, Pleasant Valley, LaGrange, Hyde Park, Pine Plains, Amenia, Dover Plains, Wappingers Falls. Coverage depends on contractor availability; tell us your town or ZIP. Before any digging, your contractor contacts Dig Safely New York (811) to get buried utilities marked.
Common questions
Is well testing required?
Not for most existing private wells. Some states and lenders require testing at sale or for new wells. Either way, the EPA recommends annual testing.
Where can I get water tested?
Use a state-certified drinking water laboratory. Your county health department can usually point you to one.
How much does a basic test cost?
Basic bacteria and nitrate tests from a certified lab are usually modest; larger panels cost more. Ask local labs for current prices.
Can I use a home test kit?
Kits are fine for screening, but use a certified lab for health decisions and real-estate transactions.
Does boiling make water safe?
Boiling kills bacteria but doesn't remove nitrate or chemicals, and it concentrates nitrate.