EPA Zone Data 2026

Iowa Radon Map, Levels & Testing Guide

Browse the 29 listed county pages surfaced for Iowa. Open a listed county to compare its EPA zone, source caveats, testing meaning, and when mitigation pricing becomes worth checking.

Zone 1
High Risk

Zone 2
Moderate

Zone 3
Low Risk

Official Evidence in Iowa

29 of 29 listed counties have official evidence

Open a county page to see the processed verdict: source confidence, local burden, state percentile, and the next step for no reading, 2.0-3.9, or 4.0+ pCi/L.

100%

covered

Measured

State source

CDC source

Needs source detail

Iowa HHS Radon Dashboard County Metrics: 29

Measured Risk Leaders in Iowa

County rankings from actual reported radon tests

These lists rank the visible Iowa county pages by measured radon signals, not by the EPA zone label alone. Use them to spot where the state hub has a real data story before opening individual county pages.

measured counties

State-level verdict

This hub has measured high-burden counties, so the first click should be evidence-led.

The state hub is now doing a decision job: it separates first-click counties, retest counties, and lower-signal counties from 29 visible county measurement rows. 6 counties cross the high measured-burden band, so those pages should answer testing and 4.0+ action questions most directly.

First-click counties

Open Sioux County first when you need the strongest local answer. It is tagged Test-now from n/a 4.0+ - 6.8 pCi/L primary - n/a tests. 18 visible measured counties are elevated or high enough to review before lower-signal counties.

Buyer/seller lane

Buyer/seller lane: start with the elevated or high counties, require a fresh lowest-level test, and turn any 4.0+ property result into quote or credit math. The hub has 29 state-source county rows to support that routing.

Retest lane

Retest lane: 2.0-3.9 pCi/L deserves more caution in the elevated/high county set than in lower-signal counties. The hub should send those users to county pages before product or cost paths.

Best county pages to open first

Start with these local evidence pages

Ranked by measured burden, 4.0+ share, test volume, and whether the EPA zone understates the measurement signal.

Sioux County

IA HHS

Test-now

n/a 4.0+ - 6.8 pCi/L primary - n/a tests

Sioux County is a first-click page: n/a of reported tests at or above 4.0 and 6.8 pCi/L primary result. Route no-reading users to a test now and 4.0+ users to quote or credit planning.

Plymouth County

IA HHS

Test-now

n/a 4.0+ - 5.4 pCi/L primary - n/a tests

Plymouth County is a first-click page: n/a of reported tests at or above 4.0 and 5.4 pCi/L primary result. Route no-reading users to a test now and 4.0+ users to quote or credit planning.

Webster County

IA HHS

Test-now

n/a 4.0+ - 5.4 pCi/L primary - n/a tests

Webster County is a first-click page: n/a of reported tests at or above 4.0 and 5.4 pCi/L primary result. Route no-reading users to a test now and 4.0+ users to quote or credit planning.

Marshall County

IA HHS

Test-now

n/a 4.0+ - 5.0 pCi/L primary - n/a tests

Marshall County is a first-click page: n/a of reported tests at or above 4.0 and 5.0 pCi/L primary result. Route no-reading users to a test now and 4.0+ users to quote or credit planning.

Highest 4.0+ share

Highest high-end reading

Most reported tests

Measured pattern

Among 29 visible counties with measurement tables, 6 land in the high measured-burden band and 18 land in high or elevated measured-burden bands. That lets this hub rank counties by observed test distribution instead of repeating the EPA map.

Map vs measurements

The strongest measured signals mostly align with the EPA zone structure, so the county pages can use the map as support while still leading with test data.

Source confidence

All measured rows shown here use state-specific official sources, so this hub can make source-backed county comparisons without leaning on a national fallback.

Already Tested