Private Wells and the Water Nobody Tests

Why this matters

A house on a private well has no utility watching its water. Nobody samples it, nobody mails a report, and in most of the country nobody requires the owner to test it at all. So the person most likely to notice that something is wrong with that water is whoever keeps replacing the parts it destroys: the plumber on the third water heater, the appliance tech pulling a scaled valve, the HVAC tech whose humidifier pad turns orange in a month. You will not diagnose the water. You can be the one who tells the owner it is time to have someone test it, and say what to test for.

Who is responsible for the water, layer by layer

Federal layer. The Safe Drinking Water Act regulates public water systems, which EPA defines as systems serving at least 25 people or 15 service connections for at least 60 days a year. A single-family private well falls below that line, so the federal drinking water standards do not apply to it and no federal rule requires the owner to test. EPA's own guidance says plainly that private well owners are responsible for the safety of their water.

State layer. States regulate how a new well is drilled, cased, located and sometimes tested at completion, through a well construction code and a licensed well contractor. Testing an existing well is a different matter. Most states require nothing of an owner who simply lives with a well. A few go further at a specific trigger: New Jersey's Private Well Testing Act requires testing when a property with a private well is sold, and some states or counties require a test before a new well is put into use or before a lender closes. Find out what your own state does; do not assume either extreme.

Local layer. County health departments often run the most useful program: subsidized test kits, a list of certified labs, and someone who will interpret a result for the owner. That office is usually where to send a customer.

The practical result is that the water's safety rests on the owner, and the owner usually does not know it.

What public health guidance actually recommends

The CDC recommends that private well owners test at least once a year for total coliform bacteria, nitrates, total dissolved solids and pH, and test more often or for more things when something changes. EPA's private well guidance gives the same core list. The reasoning behind each:

• Total coliform bacteria are an indicator group. Most are not harmful themselves; their presence means surface water or soil is getting into the well, which is the same path disease-causing organisms take. A positive coliform result usually leads to a follow-up test for E. coli, which indicates fecal contamination.
• Nitrate comes from fertilizer, manure and septic effluent. The public-system limit EPA sets is 10 milligrams per liter as nitrogen, and labs report well results against that benchmark even though it does not legally bind a private well. Nitrate matters most for infants under about six months fed formula mixed with well water, where it can interfere with the blood's ability to carry oxygen.
• Total dissolved solids and pH describe how aggressive or scale-forming the water is. These are the numbers that explain your equipment failures.

Guidance also says to test after any event that could open a path into the well: flooding over the wellhead, work on the well or pump, a nearby septic failure, or a change in taste, odor or color. Regional contaminants add to the list where geology supplies them: arsenic, uranium and radon in some bedrock regions, and the state geological survey or health department publishes where those are known.

What you see on a service call that points to the water

These are the cues a field tech is in a position to notice. None of them tells you whether the water is safe to drink, because the contaminants that make people sick are mostly invisible. What they tell you is that the water is doing something worth measuring.

The last row is the one that matters most and gets noticed least. A well cap that is cracked, missing, below grade, or sitting in a low spot where water ponds is an open door for surface water. That is a construction defect a tech can see in ten seconds while walking to the pressure tank.

Where your job stops

You do not tell a customer their water is safe or unsafe. You do not interpret a lab report for them beyond reading out what the lab printed. You do not shock-chlorinate a well unless your trade and your state license cover well work; many state well codes assign disinfection after pump or well work to a licensed well contractor, and some require it after any work that opens the well.

What you can say is specific and defensible: what you observed, why it suggests a test, what to test for, and who does it. Point the owner to a laboratory certified by the state for drinking water, usually listed by the state health department or environmental agency. A hardware-store strip test is a screening tool, not a result a lender, a doctor or a health department will act on.

If your work involves opening the water system on a well, the hazards are the pressure system and the pump circuit: shut off the pump at its breaker and bleed the pressure tank to zero before you break a fitting. The full sequence lives in Private Wells and Septic for Non-Specialists; do not improvise it.

Worked example: a pressure tank call with a baby in the house

A plumber is replacing a waterlogged pressure tank in a basement. The house is on a drilled well about 40 feet from a fenced pasture. On the walk in, she notices the well casing ends at grade inside a shallow depression, and the cap's conduit entry is open. The owner mentions they had the well tested "when they bought the house," which was seven years ago, and that the water goes cloudy for a day after heavy rain. There is a four-month-old in the house.

Reading the cues. Cloudy water after rain says surface water is reaching the well quickly. The wellhead sits in a low spot with an open entry, which is a likely path. The pasture is an obvious nitrate and bacteria source. Seven years since a test is seven times the annual interval the CDC recommends. And the infant moves nitrate from a general concern to the most time-sensitive one on the list.

What she does on the job. She shuts the pump breaker, bleeds the tank to zero on the gauge, swaps the tank, sets the precharge per the tank's instructions against the pressure switch cut-in, and restores the pump circuit only after the fittings are made up and the tank is back on its stand, watching the gauge climb to cut-out and the switch open with her hands clear of the switch cover. That is her job, and it is done.

What she says. She does not tell the owner the water is contaminated, because she does not know that.

TECH: Tank's done. Two things I noticed while I was
      out by the well, and I want you to have them.
OWNER: Okay.
TECH: The cap's sitting in a dip, and the wire
      opening on top isn't sealed. You said the water
      goes cloudy after rain. That usually means rain
      is getting into the well.
OWNER: Is it safe?
TECH: I can't tell you that, and nobody can by
      looking. A lab can. With the baby, I'd test for
      bacteria and nitrate this week, not someday.
      The county health office has kits and a list
      of certified labs.
OWNER: What do we do until then?
TECH: That's a question for them or your doctor.
      Ask it when you call. And get a well contractor
      to look at that cap.

What she writes down. On the invoice note: wellhead below grade in a depression, conduit entry open, owner reports cloudy water after rain, last test reported as seven years ago, infant in household, recommended coliform and nitrate test through a state-certified lab and a well contractor evaluation of the wellhead. Owner informed verbally. That note is the record that the observation was passed on, and it is the thing that protects both the customer and the shop.

What would change the call. If the wellhead were raised, capped tight and on a slope, and the owner had a clean test from last spring, the same pasture would rate a mention and nothing more. If the owner had said the water smelled of sewage or someone in the house had been sick, she would have told them to call the health department today and to ask them about drinking water in the meantime, rather than suggesting a test this week. If she were in New Jersey and the house were under contract to sell, the sale test would already be required, and the useful thing to say is that the cloudiness belongs in the conversation with whoever runs it.

Sampling mistakes that produce a wrong answer

When a customer asks how to take the sample, the lab's own instructions govern, and the common ways people spoil a sample are worth knowing so you do not repeat them:

• Sampling through the treatment. A softener, filter or UV unit changes what comes out. A sample meant to describe the well is drawn before treatment, often at the pressure tank's drain or a tap upstream; a sample meant to check the treatment is drawn after it. Mixing the two up produces a result that answers neither question.
• Touching the bottle's inside or cap. Bacteria samples use a sterile bottle, and a thumb on the rim is enough to produce a positive.
• Sampling right after work on the system. Pump work, a new tank or a chlorinated well will skew a bacteria result. The lab or the well contractor will say how long to wait.
• Missing the holding time. Bacteria samples typically have to reach the lab within a day or so. A sample that sat in a truck over a weekend is not a sample.

How to verify you handled it right

Read back what you put on the ticket. It should name what you saw, not what you concluded: "rust staining in fixtures" rather than "high iron," "cap below grade with open entry" rather than "contaminated well." It should name the test you recommended and who does it. And it should say the owner was told. If a later visit finds the same open wellhead and no test, that note is how you know the conversation happened, and the next tech can raise it again without starting over.

References

• EPA, Private Drinking Water Wells guidance, and the Safe Drinking Water Act definition of a public water system
• CDC, Private Ground Water Wells: testing recommendations for total coliform, nitrate, total dissolved solids and pH
• New Jersey Private Well Testing Act (testing at sale), as an example of a state-level trigger
• See related: Private Wells and Septic for Non-Specialists
• See related: Old Wells and Abandoned Casings