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Why do so many U.S. households use private wells?
Most Americans get water from a public utility, but millions of homes pump their own groundwater from a well on the property. Usually the reason is simple: there's no water main nearby, and there's groundwater under the land. This page explains how many homes are on wells, why the federal counts differ, and what it means for you if yours is one of them.
This is background, not a verdict on anyone's water. Nothing here can tell you whether a particular well's water is safe to drink. Only a state-certified lab test can show what's in it, and your local health department can help you read the results.
How many homes are on private wells?
Three federal sources count this in different ways, so the numbers don't match exactly:
| Source | What it counts | Figure |
|---|---|---|
| U.S. Census Bureau, American Housing Survey (2023) | Occupied housing units whose primary water source is an individual well | 13,863,000 homes (±738,000), about 10.4% of occupied homes12 |
| U.S. Geological Survey (2020 data) | Households in the lower 48 states with self-supplied water (usually a well, but also sources like rainwater) | About 17% of households4 |
| U.S. EPA | People and households relying on private wells for drinking water | Over 43 million people (about 15% of the population), more than 23 million households5 |
Why they differ:
- The AHS counts only the main source of water and defines an individual well as one serving five or fewer housing units. A well serving six or more units counts as a public or private system.3 It also counts only occupied homes.
- USGS counts self-supplied homes, which "typically" means a private well but can include other sources, such as capturing rainwater.4
- EPA's figures come from its own private well estimates (EPA says it released private well density estimates in 2021).5
All three point to the same picture: somewhere between about one in ten and one in six U.S. homes is responsible for its own water supply.
Why households use wells
No public water main where they live
The USGS says domestic self-supplied water, typically from a private well, "is used in areas outside of public water supply service areas" and is a common water source for homes in rural areas.4
The Census numbers show the same thing. In the 2023 AHS, 119,015,000 occupied homes got their water mainly from a public or private system (six or more units), 13,863,000 from an individual well, and 353,000 from other sources such as springs, cisterns or bottled water.13
There's groundwater under the property
Self-supplied water is "almost always from groundwater," according to USGS.6 In 2015, more than 98% of self-supplied domestic water withdrawals came from groundwater.7 Groundwater fills the spaces in soil and rock below the water table, and a well taps it. See how a private well works.
Groundwater isn't only for well owners. USGS says groundwater supplies drinking water for about 140 million people, almost half the nation, counting public systems that pump it too.8
Most people moved onto public systems
USGS says about 87% of the U.S. population gets water from a public-supply system, which it links to most people now living in urban centers. It notes a 70-year trend of people moving to urban centers, reflected in shrinking numbers of self-supplied people.6 The homes that remain on wells are mostly the ones outside those service areas.
Where wells are most common
Well use varies a lot by region. USGS reports that in 2020, the Northeast hydrologic region withdrew the most water for domestic self-supply, about 20.2% of the U.S. total (959 million gallons per day out of about 4,740).4 Each of our state pages lists that state's own figures and sources.
What being on a well means for the owner
The trade-off for having your own water is that you're in charge of it.
- Nobody tests it for you. EPA says private well water quality isn't regulated by the federal government under the Safe Drinking Water Act or by most state governments, and that well owners are responsible for their own drinking water.5 See who regulates private wells.
- Contaminants do turn up. EPA cites a USGS study of about 2,100 private wells that found roughly one in five had at least one contaminant above a human-health benchmark.5
- Testing is recommended every year. EPA recommends testing a private well annually for total coliform bacteria, nitrates, total dissolved solids and pH, and more often or for more contaminants in some situations.9 See how often to test.
- You maintain the equipment. The pump, pressure tank, casing and cap are yours to look after. See private well vs city water for the costs on each side.
Related guides
- How a private well works: drilled, dug and driven wells, aquifers, pumps and pressure tanks.
- Private well vs city water: pros, cons and costs
- Who regulates private wells?
- How often should you test a private well?
- Buying a home with a well
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U.S. Census Bureau, "AHS 2023 Table Specifications and PUF Estimates for User Verification" (Plumbing, Water, Sewage: Primary Source of Water; occupied units, in thousands). https://www2.census.gov/programs-surveys/ahs/2023/AHS%202023%20Table%20Specifications%20and%20PUF%20Estimates%20for%20User%20Verification.xlsx ↩↩
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Share calculated by Well Water Notebook from the same AHS table: 13,863 ÷ (119,015 + 13,863 + 353) thousand occupied units = 10.4%. ↩
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U.S. Census Bureau, "2023 AHS Definitions" (Primary source of water). https://www2.census.gov/programs-surveys/ahs/2023/2023%20AHS%20Definitions.pdf ↩↩
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USGS Water Resources Mission Area, "Domestic Self-Supplied Water Use" (citing Larsen et al., 2025). https://www.usgs.gov/mission-areas/water-resources/science/domestic-self-supplied-water-use ↩↩↩↩
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U.S. EPA, "Private Drinking Water Wells." https://www.epa.gov/privatewells ↩↩↩↩
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USGS Water Science School, "Domestic Water Use." https://www.usgs.gov/water-science-school/science/domestic-water-use ↩↩
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Dieter and others, "Estimated use of water in the United States in 2015," USGS Circular 1441. https://pubs.usgs.gov/publication/cir1441 ↩
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USGS Water Science School, "Groundwater Wells." https://www.usgs.gov/water-science-school/science/groundwater-wells ↩
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U.S. EPA, "Protect Your Home's Water." https://www.epa.gov/privatewells/protect-your-homes-water ↩