Well water maintenance: a yearly and seasonal checklist, and where official schedules disagree

Nobody inspects a private well for you. EPA's private wells page says it plainly: "Private well owners are responsible for delivering safe drinking water to their households." Vermont's health department adds that if you have a private well or spring, you are responsible for testing the water and maintaining the well.

The good news: the Minnesota Department of Health (MDH) says in its Well Owner's Handbook that modern wells "require remarkably little routine maintenance." Most of the job is keeping surface water and chemicals away from the top of the well, noticing when the pump starts acting differently, testing on schedule and keeping paperwork. This checklist is built only from federal, state and extension pages. Where agencies give different intervals, each is shown separately, because they really do differ.

The well maintenance schedule at a glance

On contractors, NYSDOH's consumer guide says every year, while Penn State says a professional inspection by a water well contractor every ten years, plus an annual inspection "for obvious signs of damage or contamination." CDC's yearly well checkup is a separate recommendation that doesn't say who does it. If your state health department publishes an interval, follow that one.

Well cap inspection and the rest of the wellhead

The top of the well is where most preventable contamination starts. Penn State's coliform bacteria article names a tight sanitary cap, a casing above ground and ground sloping away as simple maintenance that may eliminate a bacteria source. The evidence behind that is on our coliform bacteria page.

The cap and vent

NYSDOH's Fact Sheet #7 checklist gives the most specific cap inspection we found. Once a year, check that the cap is free of holes and cracks, securely attached and bolted on top, and that the vent is screened ("use a mirror to check for screened vent under the cap"). The next time the cap comes off for maintenance, check that it seals with an O-ring or gasket.

NYSDOH's photos explain why bolt position matters. A split cap with openings for pipes and wires, or a standard cap bolted on the side without an O-ring, can let contamination in. A sanitary or "vermin proof" cap, bolted on top with an airtight O-ring, is the acceptable type, and unacceptable caps "should be replaced with an acceptable cap." Penn State agrees: if you have a loose-fitting basic cap, consider switching to a sanitary one.

Casing height and condition

Agencies phrase the minimum height in their own words:

• Minnesota: "Keep top of well at least 1-foot above ground" (MDH Owner's Guide to Wells). If you must grade within 1 foot of the top, the handbook says to have a licensed well contractor extend the casing; Minnesota law does not allow a well to be buried.
• New York: "at least 12" above the surrounding land surface."
• North Dakota: at least one foot above ground. In flood-prone areas the North Dakota DEQ recommends two feet above the highest known flood elevation.

EPA adds a rule for everyone: "Do not cut off the well casing below the land surface." Look for cracks, holes and corrosion. MDH warns that bumping the well with trucks, mowers or snowplows "can crack the well casing, connections, or the grout seal around the well," and suggests three steel posts with flags or reflectors around a well in a high-traffic area.

Grading, drainage and pits

EPA says to "slope the area around the well to drain surface runoff away from the well." UNL Extension's spring checklist adds things most lists skip: no empty voids in the soil right around the casing, runoff from roofs and paving diverted away, and no nearby trees or deep-rooted plants that could damage the well, water line or electrical line. MDH says not to pile snow or leaves around the well.

A well in a pit is a special case. MDH says the pit "may serve as a catch basin for contaminated surface water"; extend the casing above grade and fill the pit with clean earth. Its handbook explains that pits were dug so pipes wouldn't freeze. Today a pitless adapter, attached to the casing below ground, sends water to the house through a service pipe buried deeper than the frost line.

What not to store or do near the well

Every agency says keep pollutants away. Only some give a distance, and they don't match:

For where the well itself should sit, CDC publishes a short siting list:

Those are CDC guidance numbers. Legal distances come from your state's well code and can be larger; our coliform page shows Minnesota's rule table as an example. MDH notes that Minnesota law requires the distances to be kept when you later install a septic system, fuel tank or new building, not only when the well is drilled.

• Chemicals: EPA says to avoid mixing or using "pesticides, fertilizers, herbicides, degreasers, fuels, and other pollutants near the well." UNL adds paints, solvents, oil, wood preservatives, batteries and adhesives, handled per the manufacturer's directions.
• Septic: EPA: "Never dispose of harsh chemicals, solvents, petroleum products, or pesticides in a septic system or dry well."
• Old wells: don't dispose of waste in them (EPA, MDH). In Minnesota it's illegal.
• Animals: don't tie them to the well (MDH, North Dakota).
• Hoses: MDH says never leave a hose end submerged in a tub, tank or sprayer; when filling a tank, keep an air gap of at least twice the delivery pipe's diameter.
• Fuel tanks: EPA says to regularly check tanks holding heating oil, diesel or gasoline; NYSDOH says someone should watch oil-tank refills so they don't overflow.

Pump and pressure tank: the signs, and when to call a pro

In a typical system, compressed air in the pressure tank pushes water to your taps. When pressure drops, a pressure switch starts the pump; when it rises to a preset level, the switch stops it. MDH's handbook gives typical settings of 40 to 60 psi off and 20 to 40 psi on. The tank lets the pump start and stop less often, which MDH says "serves to prolong the life of the pump."

NYSDOH's consumer guide describes a healthy pump and tank: "Water pressure is consistent, tap water looks clear, electric bills are not suddenly high, pipes are not noisy." MDH adds that "Changes in how often your pump runs, or in the smell or color of the water, can tip you off to potential problems."

Penn State's maintenance and rehabilitation fact sheet says slow decline shouldn't wait: "Delaying rehabilitation procedures can significantly increase costs and in some cases make rehabilitation impossible." It calls sand pumping "the leading cause of pump failure." Rehabilitation can involve acid and chlorine, and "chlorine and acid must never be in the well at the same time." That's contractor work.

NYSDOH says submersible pumps need very little maintenance; keep jet and suction pumps dry, and keep the tank and electrical shutoff box clear. Its checklist asks you to flush the pressure tank if necessary and exercise valves so they open and close fully.

Water testing schedule: each state's own interval

Every source agrees on a yearly bacteria test. After that they split:

Check the date on your state's page. MDH's older Protecting Your Well page (2024) still says coliform "every other year," while its testing page updated in October 2026 says every year. Go with the newest. New York also tells owners to ask the local health department whether it has its own required schedule.

A worked example: you're in Vermont, had the full Homeowner Testing Package in 2023 and a clean bacteria test last autumn. Bacteria is due again this autumn; the inorganic and gross alpha tests are due in 2028. If the 2023 nitrate result was 6 mg/L, Vermont's 3-to-6-month nitrate row applies instead. For which tests to order and how to sample, see our guide to testing well water and Which tests do I need?, then find a certified lab with the lab finder.

After floods, repairs and other events

EPA says to test immediately if conditions near the well change significantly (flooding, land disturbance, new construction), after you repair or replace any part of the well system, or when the water's odor, color or taste changes. For a smell or stain, our smell, taste and stain guide matches symptoms to tests.

Before a flood, MDH's flood precautions say to store clean water, disconnect power to the well and, if there's time, have a licensed contractor fit a watertight cap in place of the vented one. Otherwise, cover the casing top with heavy plastic secured with electrical tape, strapping or wire: "Do not use duct tape – it won't hold under flooding conditions." You'll still need to disinfect and test afterward.

After a flood, EPA says to stay away from the flooded pump to avoid electric shock, not to drink or wash with the water, and to have a well or pump contractor clean and disinfect the well before the pump goes back on. MDH says if flood water reached the well or covered the casing, assume it's contaminated; if water came within 50 feet but not to the well, you may still want to test as a precaution, without disinfecting first. Repeat rounds of disinfection and testing "may be necessary."

After repairs, MDH's handbook says a well "must also be disinfected whenever it is opened for repairs," and Minnesota law requires a licensed contractor to do it after construction or repairs. New York says to test for coliform after any modification or repair. The disinfection procedure itself, with its electrical warnings, is on our coliform bacteria page.

Treatment equipment upkeep

Ignored treatment equipment can make water worse. MDH's handbook warns that ion exchange units, including softeners, "If not regenerated at the proper frequency," can "discharge contaminants into the drinking water at concentrations greatly exceeding the untreated water concentrations." NYSDOH says poorly maintained systems "can result in failure of water treatment and loss of water pressure," and to follow the manufacturer's recommendations. Only two intervals below are numbers; the right schedule depends on the unit and your water.

MDH says that if you treat, test the water after it goes through treatment. Choosing equipment rather than maintaining it? Start with our treatment guide by test result.

Seasonal notes: spring, drought, winter

Spring. CDC's mechanical check falls here, and UNL notes winter "can be especially hard on outdoor systems." It suits the yearly bacteria sample too: Penn State says the most bacteria are found shortly after several weeks of rainy weather and the fewest in dry, cold winter conditions.

Late summer and fall. Penn State's drought guidance says Pennsylvania groundwater tends to peak in March and April and usually bottoms out in late September or October, so "most problems with wells tend to occur in late summer or early fall." Shallow hand-dug wells "are often the first wells to dry up"; deeper wells may hold out longer but take longer to recover. Conserve "as soon as drought conditions occur." If water drops below the pump, lowering it is usually short-term; Penn State says to consult a local well driller or a professional hydrogeologist.

Winter. Mark the well so plows don't hit it (MDH) and don't pile snow on it (MDH, North Dakota). If your well still sits in a pit, MDH recommends having a licensed well contractor extend the casing above ground and install a pitless unit or adapter.

Record keeping: build a well file

Penn State explains why records matter: to detect a decline in performance "you must have a point of reference," usually the construction and pump-test data on the well completion report or log. Keep:

• the well log: depth, date drilled, casing, grouting, screen and yield in gallons per minute (Penn State);
• every water test result (Penn State, MDH, NYSDOH);
• inspection reports and contractor invoices, including pump replacement (Penn State);
• treatment equipment warranties, invoices and manuals (Penn State);
• records of disinfection or sediment removal "that may require the use of chemicals in the well" (EPA);
• completed yearly checklists (NYSDOH), and failures and repairs (Oregon Health Authority);
• sealing records for any old wells on the property (MDH).

Lost the log? Try the Minnesota Well Index, Wisconsin DNR's well records search (its Well Construction Report shows drillhole and casing depth), Pennsylvania's PaGWIS, or North Dakota's State Water Commission database.

How long will a water well last?

There is no fixed lifespan. The Minnesota Department of Health says: "Wells have a life expectancy that can vary considerably. While some wells may last 100 or more years, a life of 25 to 50 years is more common" (MDH, Finding Lost Wells: Searching for Wells on a Property, updated October 18, 2024). Penn State Extension describes how a well wears out: "As a water well ages, the rate at which water may be pumped (commonly referred to as the well yield, flow or performance) tends to decrease, especially in wells that were not properly developed when first drilled," and "Corrosion of metal casing and other well components can seriously reduce the useful life of a well". Its signal for action is the drop in yield of 25 percent or more from the pump table above, measured against the original figures on your well log, which is one more reason to keep the well file. The pump is a separate part with its own wear, covered in the pump and pressure tank section.

Age doesn't excuse a well from testing: keep the yearly bacteria test whatever the well's age. And when a well reaches the end of its life, CDC says to retire it by filling and properly sealing it, and states such as Minnesota and Wisconsin require it (next section); it shouldn't just be left in the ground.

Unused and abandoned wells

CDC says that if you no longer use your well, "you must retire it by filling and properly sealing it," and "In many states, well owners must document retired wells." MDH explains why: "An unused well can act like a drain," giving runoff and waste a direct path into groundwater. If you might use the well again, CDC says to keep maintaining it.

In Minnesota and Wisconsin sealing isn't a DIY job. Minnesota law says only an MDH licensed well contractor may seal a well, and an unused well without a Water Well Maintenance Permit must be sealed. Wisconsin says that since June 1, 2008, only licensed well drillers and pump installers can fill and seal wells. EPA says to hire a certified well driller for abandonment. How to find a hidden old well, other states' sealing rules, what sealing costs and which programs help pay are in our old water well guide.

Next step

Pick a date this spring: walk the wellhead with the table above, send a bacteria sample to a certified lab (the lab finder filters for bacteria), and start a well file with the paperwork you have. If something fails, or the pump starts acting differently, call a licensed well contractor before it becomes an emergency.

This page is general information, not professional or medical advice. Rules and recommended intervals differ by state and county; follow your own state's well code and health department. For decisions about an infant, a pregnancy or someone who is ill, ask a doctor or your health department.

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