Last checked: October 22, 2026

How to document your well before nearby construction or heavy pumping

If a quarry, highway, pipeline, gas well, subdivision, data center or any other large project is coming near your home, the most useful thing you can do is record your well's condition before work starts. If your water level drops or your water changes later, a contractor, state agency or court will want to know what it was like before. This page covers what to record, how to make the records hold up, and who to call.

Why a "before" record matters

Two rules show how much weight a pre-project record can carry:

• Pennsylvania gas wells. State law presumes an unconventional gas well operator is responsible for pollution of a water supply within 2,500 feet of the well if it happens within 12 months of drilling, completion, stimulation or alteration. One way the operator can rebut that is a pre-drilling survey showing the pollution was already there.¹ Pennsylvania's rule also lets a homeowner do their own pre-drilling survey to support a future claim, using an independent Pennsylvania-accredited lab and its chain-of-custody procedures.²
• Coal mine blasting. Under federal surface coal mining rules, the operator must tell residents within ½ mile of the permit area how to request a pre-blasting survey at least 30 days before blasting. The survey documents existing damage, and wells and other water systems "warrant special attention," although the check may be limited to surface conditions and readily available data. You get a copy and can file a written disagreement.³

Most construction projects come with no such rule, so it's up to you to build the record.

Step 1: Gather the paperwork you already have

• Well log (well completion report). It records depth, casing and often the water level when the well was drilled. Many states keep these online; see your state page.
• Past lab reports, including any from when you bought the home (buying a home with a well).
• Service records: pump and pressure tank work, well repairs, treatment equipment installs, with dates and invoices.

Step 2: Have the water level and yield measured

• Static water level is the depth to water when the pump hasn't run for a while. USGS's standard method uses a graduated steel tape, which it calls the most accurate method for non-flowing wells of moderate depth. It isn't recommended while the well is pumping, and each reading is taken from a marked, fixed measuring point.⁴
• Hire a licensed well contractor to take the reading and run a flow (yield) test. Ask them to write down the date, time, how long the pump was off beforehand, the measuring point they used, and the method. Leave this to the contractor rather than opening the well yourself.
• Repeat in the same season. Water levels move with pumping, recharge and the seasons, and they can fall a lot in a drought, so one reading has limits. Readings from the same season each year are easier to compare.⁵

Step 3: Get a lab test that will hold up

1. Use a state-certified lab. EPA recommends testing every year for total coliform bacteria, nitrates, total dissolved solids and pH, and right away if the taste, odor or color changes.⁶ Ask your health department which contaminants are common locally.⁶
2. Add tests that fit the project.
   • Sediment or turbidity, iron and manganese near blasting or excavation. A 2026 Georgia lawsuit says data center blasting and excavation let sediment into neighbors' wells; Meta disputes the claims.⁷
   • Chloride and TDS where heavy pumping could pull in salty water, and arsenic, uranium or radium where USGS has seen pumping change water chemistry.¹⁶¹⁷ The data center testing guide explains these.
   • Methane and other gas-related tests near oil and gas drilling. Ask your state program or the lab what it recommends.
3. Ask for chain of custody. Pennsylvania's pre-drilling rule relies on an independent accredited lab and the lab's chain-of-custody and sample-handling procedures.² Even where no rule applies, ask the lab whether it offers chain-of-custody sampling, since that's the standard Pennsylvania's rule relies on.
4. Note where the sample came from: which tap, and whether the water passed through treatment (softener, filter) first.²

Keep the full report, not just a summary, and compare the numbers with EPA benchmarks in our Well Test Results Checker.

Step 4: Take dated photos and video

• The wellhead, cap and casing, and the ground around them.
• The pressure tank, pressure switch and gauge (with the reading visible), and any treatment equipment.
• A clear glass of water from the kitchen tap and from an untreated tap, in daylight.
• Fixtures, toilet tanks and laundry if you already see staining.
• The house foundation and other structures, if blasting is planned.

Most phones save the date with each photo. Save copies off your phone (email them to yourself or print them).

Step 5: Keep a simple log

Write down project milestones (clearing, blasting, dewatering, pumping tests, start of operation), droughts, and anything unusual: pressure drops, air in the lines, sediment, new taste or smell. Keep receipts for any well work and for bottled water. Minnesota, for example, asks for those receipts with a well interference complaint.⁹

Step 6: Find out what the project plans

• Planning and zoning files often name the water source and any wells. Ask whether the project will pump groundwater for supply or to dewater excavations.
• Dewatering permits. Some states regulate temporary construction pumping. Minnesota has a general permit for temporary dewatering (up to 50 million gallons a year, finished within a year), Indiana requires construction dewatering to be reported, and Virginia excludes temporary dewatering under 24 months from its groundwater permits.¹¹¹²¹⁴
• Permanent wells. See who regulates big groundwater pumpers for state thresholds and where to search permit applications.
• Ask for monitoring. At hearings, ask whether the project will monitor groundwater levels and what happens if nearby wells are affected. NGWA suggests communities ask for a monitoring plan.¹⁵

If something changes

1. Call a licensed well contractor. Wells fail for mechanical and electrical reasons too, and Minnesota's DNR wants a contractor's report before it investigates.¹⁰
2. Retest the water with the same lab and tests if you can, so the results compare cleanly. Until results are back, ask your health department whether to use another water source for drinking.
3. Contact the right agency: your local health department for water quality, and your state water agency for water-level problems near large pumping. Minnesota and Indiana both investigate well complaints near high-capacity pumping.¹⁰¹³ For coal mine blasting, contact the state mining regulator; for Pennsylvania gas wells, the state Department of Environmental Protection.³¹
4. Don't seal or abandon the well until any investigation is finished. Minnesota dismisses complaints if the well was sealed first.¹⁰
5. Write to the project operator with dates and copies of your records, and keep a copy.

Caveats

• Baselines have limits. Water levels and some water-quality numbers vary with season and pumping, so one test isn't the whole story.⁵
• A baseline can't prove cause. The Georgia lawsuit is unresolved, and part of Indiana's 2025 investigation was still open when it was reported.⁷⁸
• Rules differ by state. The Pennsylvania and coal blasting rules above apply only to those activities. Check with your state before relying on any deadline or remedy.

Frequently asked questions

How far ahead should I test? Before any work starts, and early enough to get results back. Pennsylvania's rule for operator surveys requires results to reach the state 10 business days before drilling, which gives a sense of the timing involved.²

Should I let the company test my well? That's your decision. In Pennsylvania, refusing an operator's pre-drilling survey can void the presumption that protects you.¹² Many owners also hire their own certified lab so they have an independent result.

Is a home test kit enough? For a baseline you may need to rely on later, use a state-certified lab and keep the full report.⁶²

How often should I repeat it? At least the EPA yearly set every year,⁶ plus a water-level reading in the same season each year.⁵ Retest any time something changes.

Does homeowners insurance cover a well that goes dry? Policies vary. Ask your insurer and keep the same records described here.

Where to get tested and treatment options

Related guides

• Free tool: Well Test Results Checker: type in your lab numbers and see each one next to the EPA benchmark.
• Who regulates big groundwater pumpers?
• Data centers and water testing: a baseline for your well
• Will a nearby data center affect my well?
• How often to test a private well
• How a private well works