Radon in Linn County, IA: Test Data and Mitigation Cost

Iowa is the radon state. According to Iowa HHS, the Iowa Radon Survey found 71.6% of homes at or above EPA's 4 pCi/L action level, the largest share in the country, and EPA places all 99 Iowa counties, Linn included, in Zone 1.

Closer to home, Linn County Public Health's December 2025 environmental health report counts 709 radon tests in Linn County homes from 2020 through 2023. The yearly average of those home test kits ran 1.7 pCi/L in 2020, 1.2 in 2021, 2.5 in 2022 and 2.7 in 2023, per the report's Figure 14.

Those averages are lower than the statewide survey would suggest, and the report itself explains why that should not reassure anyone: it states that all Linn County residents are at risk of indoor levels above 4.0 pCi/L and that testing is the only way to know. A yearly average blends many low first-floor readings with the high basements that drive mitigation work.

Licensing and permits

State rules: Iowa credentials radon measurement and mitigation work through Iowa HHS under Iowa Administrative Code 641, Chapter 43. Ask any Cedar Rapids bidder for their Iowa credential number and check it with the Iowa HHS radon program before signing.

Home sales: Iowa HHS notes there is no state rule requiring a test or a fix at sale, but under Iowa Code 543B a seller must disclose any known radon tests, with dates and results, and give the buyer the Iowa Radon Home-Buyers and Sellers Fact Sheet.

New homes: Iowa HHS lists Linn County among the 11 jurisdictions that required radon-resistant new construction before the statewide rule, and Linn County Public Health says new single-family homes in unincorporated Linn County must include those features. From July 1, 2026, the state building code requires a passive radon system (IRC 2021 Appendix AF) in new one- and two-family homes statewide.

Local permits: Cedar Rapids, Marion and Hiawatha run their own building and electrical permit desks; a new fan circuit can need an electrical permit. Where one applies, HomeGuide's survey lists radon permit fees of $25 to $150.

Local conditions

What the county data shows: Linn County Public Health maps short-term radon results by ZIP code (Figure 15 of its report), and the chapter's summary says indoor radon testing continues to show elevated levels across the county.

Passive pipes are common here: because Linn County required radon-resistant construction in unincorporated areas before the 2026 state rule, many newer rural homes already have a vent pipe through the roof. EPA's Citizen's Guide notes such a passive system can be activated with a fan if a test still reads high.

Low cheap-kit numbers are not a clean bill of health. The county's yearly averages rose from 1.2 pCi/L in 2021 to 2.7 pCi/L in 2023, a reminder that results move with season, test location and who chose to test.

What drives local prices

A single suction point through a poured basement floor, the usual fix in Cedar Rapids and Marion subdivisions, runs $1,200 to $2,000 installed in HomeGuide's February 2026 cost survey (national average $1,600).
Older homes on hollow block walls near downtown Cedar Rapids may need block-wall suction at $1,800 to $3,000, per the same survey.
Turning an existing passive pipe into an active system usually costs less than a new install because the pipe run is already in place; our calculator treats a mixed foundation at est. ×1.5 and a large house (2,500-plus sq ft) at est. ×1.25.
HomeGuide lists a professional retest at $125 to $400 and a do-it-yourself kit at $10 to $30; Linn County Public Health sells low-cost test kits to residents.
EPA's 2010 guide put yearly fan electricity and heating loss for a sub-slab system at $50 to $200 (2010 dollars).

Common jobs

Basement floor systems in Cedar Rapids, Marion and Hiawatha subdivisions built before the county's construction rule.
Activating passive vent pipes in newer homes around Robins, Ely and Fairfax.
Block-wall and crawlspace work on older farmhouses near Mount Vernon, Lisbon and Center Point.
Inspection-period testing and fixes tied to Iowa's seller disclosure form.

From test to fixed, and where we cover

Step 1: test the lowest lived-in level, or buy a kit from Linn County Public Health. Step 2: if the result is 4 pCi/L or higher, confirm it with a second test, as EPA advises.

Step 3: get two itemized bids from Iowa-credentialed mitigators and compare them with the calculator. Step 4: retest no sooner than 24 hours after the fan starts and within 30 days, per EPA's Consumer's Guide.

We cover Cedar Rapids, Marion, Hiawatha, Robins, Mount Vernon, Lisbon, Center Point, Fairfax, Ely, Palo and Springville, along I-380, US 30, US 151, IA 100 and IA 13.

Communities: Cedar Rapids, Marion, Hiawatha, Robins, Mount Vernon, Lisbon, Center Point, Fairfax, Ely, Palo, Springville

Before you sign

A high result means planning a fix in the coming weeks, not an emergency (EPA Citizen's Guide). Confirm it, check the Iowa credential, and get the reduction guarantee in writing.

Questions about Linn County

How much radon testing has Linn County done?

Linn County Public Health counts 709 home tests in 2020 through 2023, with yearly averages between 1.2 and 2.7 pCi/L.

Is Iowa really the highest radon state?

Iowa HHS says the Iowa Radon Survey found 71.6% of homes at or above 4 pCi/L, the largest share of any state.

Do I have to test before selling a house in Cedar Rapids?

No state rule requires it, but Iowa sellers must disclose known test results and hand over the state fact sheet, per Iowa HHS.

What does a system cost in Linn County?

HomeGuide's 2026 survey puts a standard floor system at $1,200 to $2,000 and block-wall work at $1,800 to $3,000.

Sources

Related radon guides

Rules and fees change; confirm with the state radon office. Price your own system with the radon mitigation cost calculator, read the radon mitigation cost guide, or check any ZIP with the radon levels by ZIP tool.