If the water does not come from a utility bill, it comes from a well, a spring, or a cistern. A drilled well is a hole, a casing, a pump, and an aquifer that may or may not keep up with a modern house. The listing will say "private water" or it will say nothing and show a pressure tank in a photo by accident. The facts you need are yield, water quality, and the age of the equipment. None of those are in the granite-counter sentence.

This is not septic, but the two travel together often enough that you should order both inspections in the same window. A house can have city water and a septic tank, or a well and city sewer. Read the utilities line twice.

What it is

A drilled well is the common modern version. Dug wells and springs are older, shallower, and easier to contaminate. The pump is either submerged in the well or sitting in the basement as a jet pump. A pressure tank in the basement holds a cushion of water so the pump is not starting every time you wash your hands. Yield is gallons per minute under a proper test, not "the shower felt fine." Quality is a lab panel: bacteria, nitrates, and whatever the local geology adds, which might be arsenic, lead, radon in water, or salt from an old intrusion.

How to spot it in the listing

No water-district line on the tax record, a rural road, "well" in the utilities, or a pressure tank visible in the utility-room photo. Remarks that say "city water available" have the same trap as "sewer available." Available is not connected. Ask which it is, and ask for the well log. Drillers file logs with the state in many places: depth, casing, and the yield the day it was drilled. That yield is not today's yield, but a log that says 1 gallon a minute was never a great well. Research beyond the listing includes the state well database. Use it before you offer if the record is online.

How to spot it at the showing

Find the pressure tank and the well head, the cap in the yard. A buried, unmarked well is a maintenance problem the moment the pump dies. Look at the cap: sealed and vented correctly, or a cracked cover a bug could enter. Run water at two fixtures for several minutes. A well that cannot recover will fade to a trickle and the pump will short-cycle. Look for treatment equipment: a softener is hardness, a UV light is a bacteria strategy, a reverse-osmosis tap at the sink means someone did not want to drink the rest of the plumbing. Ask why each canister is there. "The guy installed it" is not a water test.

Taste and clarity are not a bacteria test. Coliform sampling has a holding time. Order it at the start of the inspection period so the lab result exists before you waive.

The real risk

A well that does not yield enough water for the house, a contamination hit that needs treatment forever, or a pump and casing failure that is a five-figure surprise because the well is 400 feet down. Drought and nearby new wells change yield. A test on a wet April is the optimistic number. It is still the number you can get during a normal contingency, so get it, and read it next to the driller's original log.

Insurance and lending

Homeowners insurance does not replace a dry well. Some policies have limited coverage for pump failure from a lightning strike or a sudden break, with exclusions for age. Ask. Lenders, especially FHA and VA, often require a water test for bacteria and sometimes nitrates, and they want a safe distance from the septic. A positive coliform test can stop an FHA loan until it is clear and retested. Conventional lenders vary and many still want the test if it is in the purchase contract. Put the test in the contract. Do not rely on the lender to care more than you do.

Typical cost ranges

Typical ranges, not quotes.

Basic lab panel (bacteria, nitrates, and a local add-on or two): often $150 to $400. A broader metals panel costs more and is worth it where arsenic or lead is a known geology.
Yield or flow test by a well contractor: often $200 to $600.
Pressure tank or a standard pump replacement at moderate depth: commonly $1,500 to $4,000.
Deep pump replacement: often $3,000 to $7,000 or more.
New well when the old one has failed and cannot be rehabilitated: commonly $8,000 to $25,000 or more, entirely dependent on depth and the local rock. Treatment systems (UV, softener, arsenic media) are often $800 to $4,000 installed, plus media changes forever.

Pass, negotiate, or investigate

Investigate every private water source with a lab test and a look at the log. Negotiate treatment, a pump, or a credit when the test fails or the yield is marginal for the house. A credit that ignores a failed bacteria test is how you move into a boil-water house. Pass when the yield cannot support the occupancy, a new well is speculative, and the seller will not escrow the drilling. A good well with a clear test and a known pump age is a normal rural house. Maintain it. The inspection checklist should list the lab hold time so you do not order the test on day nine of a ten-day contingency.

Well Water: Yield, Bacteria, and the Test the Listing Will Not Include