Ottawa, IL Radon Levels

Q: What EPA Radon Zone is Ottawa in?

Ottawa is in La Salle County, EPA Zone 1.

Q: Why are radon readings shown from areas near Ottawa?

No homeowner radon tests have been submitted for Ottawa yet, so readings from the closest cities and the La Salle County average are used as the best available indicator of local conditions. The EPA recommends testing every individual home.

Q: How much does radon mitigation cost in Ottawa?

Radon mitigation typically costs between $800 and $2,000. Most standard systems fall in the $1,000-$1,500 range.

Check local Ottawa radon levels and find certified testing and mitigation professionals to keep your home safe

Ottawa, IL Radon Facts

EPA Radon Zone Zone 1 — High Risk > 4.0 pCi/L (Zone 1)

County La Salle County, IL

Zip Code 61350

Located in La Salle County along the Illinois River valley, Ottawa sits where alluvial soils and underlying Ordovician limestone create variable radon conditions. Testing data for the 61350 zip code area remains limited, making professional radon testing essential for homeowners. Many local homes feature full basements typical of the region, which can concentrate radon gas when present.

8.00

pCi/L area average

Above EPA Action Level

La Salle County average: 8.00 pCi/L, based on 5 user-submitted tests across 4 cities in the county. No homeowner readings have been submitted for Ottawa itself yet, so this county figure is the closest available benchmark. The EPA recommends taking action at or above 4.0 pCi/L.

4.0 EPA

10+

Ottawa, IL Radon Mitigation

Professional radon mitigation is the most effective way to permanently lower radon levels and protect your household.

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Radon Readings Near Ottawa, IL

No homeowner tests have been submitted for Ottawa yet. The closest cities with user-submitted radon data are shown below — explore them to gauge local conditions. Radon varies by home, so testing is the only way to know your level.

City	Distance	Avg User Level	Readings
Marseilles	7.8 mi	9.00 pCi/L	1
Peru	14.8 mi	6.50 pCi/L	2
Streator	15.9 mi	7.00 pCi/L	1
Earlville	16.5 mi	11.00 pCi/L	1
Spring Valley	18.9 mi	2.00 pCi/L	1
Newark	20.3 mi	11.00 pCi/L	1
Ancona	21.5 mi	20.00 pCi/L	1
Plano	26.8 mi	10.00 pCi/L	1

La Salle County Radon Profile

The bedrock and soils beneath La Salle County are classified by the EPA as Radon Zone 1, the highest-risk tier, with predicted average indoor screening levels above 4 pCi/L. Homeowner-submitted tests from 4 cities in La Salle County average 8.00 pCi/L across 5 tests — above the EPA's 4 pCi/L action level, reinforcing the need for testing across the county. Radon is the second leading cause of lung cancer in the United States, and a short-term test is the only way to confirm a specific home's level in La Salle County.

Radon FAQ for Ottawa, IL

What EPA Radon Zone is Ottawa in?

Ottawa and the 61350 zip code are in La Salle County, which has an EPA assigned Radon Zone of 1. A zone of 1 predicts an average indoor radon screening level greater than 4 pCi/L.

Why are radon readings shown from areas near Ottawa?

No homeowner radon tests have been submitted for Ottawa yet. Because radon is driven by regional soil and bedrock geology, readings from the closest cities—and the La Salle County average—are the best available indicator of local conditions until Ottawa homeowners submit their own results. The EPA still recommends testing every individual home, since levels can vary significantly from house to house.

How much does radon mitigation cost in Ottawa?

Radon mitigation in Ottawa typically costs between $800 and $2,000. Most homes with standard basements can be mitigated with a sub-slab depressurization system in the $1,000–$1,500 range. Factors that can increase cost include complex foundations, crawl spaces, or very high radon levels.

Should I test for radon if I'm buying a home in Ottawa?

Yes. Radon testing should be part of every home purchase. A short-term radon test is typically included as part of the home inspection process and costs $150–$250. If elevated levels are found, you can negotiate mitigation as part of the sale.