Lancaster County Radon Data: How Lincoln Compares to Its Neighbors

Last reviewed 2026-07-25. Journalists, researchers, and community groups are welcome to cite any figure on this page with attribution and a link.

Nebraska requires the Department of Health and Human Services to report the number of radon tests conducted and the average level by county, and that report is filed with the Legislature. The edition used on this page covers measurements taken from October 1, 2018 through September 30, 2023. Every figure below comes from that report, from the two Nebraska statutes that depend on it, from Nebraska DHHS construction guidance, or from EPA's published action level. Nothing here is estimated, rounded, or interpolated, and every source is linked at the bottom.

The short version for a Lincoln homeowner: Lancaster County produced 19,828 measurements averaging 3.6 pCi/L, alongside Douglas County's 21,089 averaging 3.9. That Lancaster average sits below the 4 pCi/L level at which EPA recommends a home be fixed, and above the 2.7 pCi/L threshold Nebraska uses to exempt a county from radon resistant new construction. The four neighboring counties in the table below all reported higher averages, several of them close to double. Lincoln looks moderate on its own county line and is ringed by counties that do not.

How Lancaster County compares with the counties around it

The table below is transcribed from the Nebraska DHHS report filed with the Legislature under Neb. Rev. Stat. 76-3507. The report's own columns are the county name, the total number of measurements, the average radon level in pCi/L, and whether that average exceeds 2.7 pCi/L. The last column is not decoration. It is the trigger for the county exemption in section 76-3505, and every county listed here answers yes to it.

Two things stand out. Lancaster and Douglas, the two largest test counts in this table by an order of magnitude, are also the only entries under 4 pCi/L. The rural counties around Lincoln, each with a few hundred measurements, run from 6.7 up to 7.9. Whether that pattern reflects geology, foundation practice, or simply which homes get tested, the report does not say, and neither will we.

What the 2.7 pCi/L figure in Nebraska law actually controls

Neb. Rev. Stat. 76-3505 is the exemption section. It provides that new construction after September 1, 2019 shall not be required to use radon resistant new construction if the project utilizes the design of an architect or professional engineer licensed under the Engineers and Architects Regulation Act, if it is located in a county in which the average radon concentration is less than two and seven-tenths picocuries per liter of air as determined by the department pursuant to section 76-3507, or, other than for any residential dwelling unit, if a local building official makes a determination after review that radon resistant new construction is not necessary.

The middle clause is the one Lincoln homeowners ask about, and it is settled by the same DHHS report the statute points at. Lancaster County's reported average is 3.6 pCi/L. Two and seven-tenths is 2.7. Lancaster is above it, so the county exemption does not reach Lincoln, and on these figures it does not reach Gage, Saline, Saunders, or Seward County either. A Lincoln project would have to qualify some other way, and the third clause is expressly unavailable for any residential dwelling unit.

What Nebraska requires under and around a new Lincoln slab

Because Lancaster County does not qualify for the exemption, anything built in Lincoln after September 1, 2019 that is intended to be regularly occupied by people falls under Neb. Rev. Stat. 76-3504. The specifications in the table are transcribed from that statute and from the Nebraska DHHS radon resistant new construction requirements document. Together they describe a passive system: it moves soil gas without a fan, and it deliberately leaves a powered upgrade path open for later.

The electrical circuit is the tell. The state did not require a fan. It required a place to put one. That distinction is the most misunderstood thing about newer Lincoln housing, because a buyer who spots a white pipe running up through a mechanical chase often assumes the radon question has been answered already. It has not been. The pipe is infrastructure. The answer is a measurement taken in the living space after the house is occupied and running normally.

How much radon testing has actually happened around Lincoln

Test counts vary enormously by county, and that matters when you try to reason from local experience. Lancaster County's 19,828 measurements over five years mean a Lincoln homeowner can usually find a neighbor who has tested. Saline County's 289 over the same period mean a Crete homeowner generally cannot. Saunders reported 801, Gage 726, and Seward 621. Those are the raw counts as filed; the report does not adjust them for population, housing stock, or foundation type.

The statewide picture is blunter. Nebraska DHHS states that the results of more than half of radon tests in the state are above the action level of 4.0 pCi/L, and describes Nebraska as having a very high incidence of radon in homes. That statement is about tests submitted across Nebraska, not about all Nebraska homes and not about Lancaster County in particular, which is precisely why the county table above is the more useful instrument for anyone deciding what to do about one house in Lincoln.

What these numbers cannot tell you about a specific address

A county average is an average of submitted measurements. It is not weighted, it does not adjust for foundation type, and it carries no information about any individual house. Two Lincoln homes on the same street can produce results that differ several times over depending on slab condition, whether the sump crock is sealed, how deep the foundation sits, and how tightly the house is run through a Nebraska winter. The report is a map of the terrain rather than a reading on your basement.

EPA writes its guidance at the level of the individual home for that reason. EPA recommends homes be fixed if the radon level is 4 pCi/L or higher, and also recommends that Americans consider fixing their home for radon levels between 2 pCi/L and 4 pCi/L, stating there is no known safe level of exposure to radon. Nebraska adds a professional layer on top: under Title 180, Chapter 11 of the Nebraska Administrative Code, a business must not conduct measurements without a radon measurement specialist and must not conduct mitigations without a radon mitigation specialist.

Sources & Methodology

Every figure above was taken from the primary sources below (accessed 2026-07-25). Where a number is derived (arithmetic on published figures) or covers a broader period or area, the text says so.

1. Nebraska DHHS Report on Number of Radon Tests Conducted and Average Level by County — Every county measurement count and average on this page: Lancaster 19,828 at 3.6 pCi/L, Douglas 21,089 at 3.9, Saunders 801 at 6.7, Saline 289 at 6.8, Seward 621 at 7.0, Gage 726 at 7.9. Covers October 1, 2018 through September 30, 2023.
2. Neb. Rev. Stat. 76-3505, Radon Resistant New Construction Exemptions — The 2.7 picocuries per liter county exemption threshold, the September 1, 2019 date, the architect and engineer clause, and the local building official clause that excludes residential dwelling units.
3. Neb. Rev. Stat. 76-3504, Radon Resistant New Construction Requirements — The three-inch gas-tight vent pipe, the twelve inches above roof surface and ten feet from openings requirements, sealed and trapped sump lids, the attic electrical circuit, and the Radon Reduction System label.
4. Nebraska DHHS Radon Resistant New Construction Requirements and Recommendations — The four inches of clean aggregate gas permeable layer, the aggregate size range, and the 6 mil polyethylene or 3-mil cross-laminated soil-gas retarder overlapped 12 inches at the seams.
5. U.S. EPA, What Is EPA's Action Level for Radon and What Does It Mean? — The recommendation that homes be fixed at 4 pCi/L or higher, the recommendation to consider fixing between 2 and 4 pCi/L, and the statement that there is no known safe level of exposure to radon.
6. Nebraska DHHS Radon Program — The statement that results of more than half of radon tests in the state are above the action level of 4.0 pCi/L, and that Nebraska has a very high incidence of radon in homes.
7. Nebraska Administrative Code Title 180 Chapter 11, Radon Measurement and Mitigation Services — The operating requirement that a business must not conduct measurements or mitigations without the corresponding specialist, and the record-keeping requirement covering pre-mitigation and post-mitigation measurements.