How deep is my well? Finding your well record

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The well log is the place to start.

When a well is drilled, the driller writes up a report. It goes by a few names: well log, well completion report, driller's log or construction report. Pennsylvania law, for example, requires a driller to fill one out for every well.

A well log usually lists the total depth, how the well was built (casing size and depth), the water level, and the layers of soil and rock the driller went through. Many also list how many gallons per minute the well produced. Some records have less: Pennsylvania's geological survey says some of its records hold only the owner, address, driller and date drilled.

Here's where to look for yours.

1. Your state's well database. Many states let you search well records online by address, county or owner. Pennsylvania's is the Groundwater Information System, run by its geological survey. Minnesota's is the Minnesota Well Index. Minnesota notes that most wells built there before 1974 aren't on file.
2. Your closing papers. Home inspection and well inspection reports often include the depth.
3. A well disclosure. Some states require sellers to disclose wells. In Minnesota you can look up past well disclosure certificates online.
4. The driller. If you know who drilled the well, ask. Penn State suggests asking the driller for a copy.
5. Your county health department. Some keep their own well permits.

A contractor can measure it if there's no record.

A licensed well contractor can measure the total depth and the water level. The National Ground Water Association's yearly checkup includes measuring the water level before and during pumping. Ask for both numbers when you schedule it.

Wells vary a lot in depth.

The EPA describes 3 kinds of private wells:

In Pennsylvania, Penn State says wells run from under 10 feet to over 1,000 feet, and the average is usually 100 to 200 feet. Our county pages at /well-water/ show typical depths from well records near you, where they exist.

Shallow wells need more testing.

The Minnesota Department of Health says dug, bored and driven wells are often less than 50 feet deep and are more likely to be contaminated by surface water, septic systems or chemical spills. It recommends testing old wells and wells under 50 feet deep more often, because their water can change after heavy rain or snowmelt.

The EPA also flags shallow and older wells for floods. Wells more than 10 years old or less than 50 feet deep are likely to be contaminated after a flood, even with no visible damage. See what to do after a flood.

You need the depth to shock the well.

To shock chlorinate a well, you need to know how many feet of water are standing in it. That's the total depth minus the depth to water. Our shock calculator turns those numbers into a bleach amount.

Questions people ask