Radon Testing & Mitigation in Harrisburg, PA
Moderate radon risk from Great Valley folded sedimentary bedrock — shale and sandstone on the ridges, limestone and dolomite beneath the valley floors. Susquehanna River valley geology creates variable radon entry potential across Dauphin County.
High Radon Risk Area
Harrisburg sits in EPA Zone 1 — testing is recommended for every home regardless of age or foundation type.
Radon Testing in Harrisburg
In Harrisburg-area ZIP codes, 49% of 19,862 basement tests reported to PA DEP measured 4.0 pCi/L or higher, with a median of 3.8 pCi/L. Readings differ from house to house, so each home needs its own test. Start with a short-term test of 48–96 hours on the lowest lived-in level. A long-term test of 90 days or more averages out seasonal swings.
A result at or above EPA's 4.0 pCi/L action level calls for a confirming test or mitigation. Retest after a mitigation system goes in, and at least every two years from then on. Pennsylvania requires DEP certification for anyone who tests as a paid service; you may test your own home with a kit from a DEP-certified laboratory. For a home sale, read the Pennsylvania real estate radon testing guide.
Local Geology & Risk Factors
Harrisburg is located in an area with Great Valley / Folded Sedimentary Belt geology, which contributes to elevated radon levels. The Pennsylvania DEP identifies this region as having significant radon potential due to uranium-bearing rock formations.
Testing is essential because radon levels can vary significantly between neighboring homes based on construction, soil permeability, and ventilation.
See Pennsylvania radon levels and EPA radon zone classifications →
Harrisburg is the seat of Pennsylvania state government — the city where the DEP is headquartered and where radon policy is made. State government employees, legislative staff, and contractors regularly relocate to the Harrisburg metro — often from regions with different radon risk profiles and different testing cultures. A transplant from Philadelphia may be familiar with Zone 1 radon testing expectations. A transplant from western PA may have less radon awareness. The communities immediately west of the Susquehanna River — Camp Hill, Lemoyne, New Cumberland, and Wormleysburg — sit in Cumberland County, which is classified Zone 1. Harrisburg-area homebuyers who cross the river to the West Shore are crossing a geological boundary, not just a county line.
Quick Facts
- Median home value: $121,000 · Median year built: 1947
- Population: 50,092
- Foundation types: Basement (common in older homes); Slab-on-grade (newer suburbs); Crawlspace (rural areas)
Dauphin County Context
Harrisburg is a municipality of Dauphin County, EPA Zone 1. Zone designation is assigned at the county level, so Harrisburg inherits its classification; countywide aggregate figures live on the county page.
See Dauphin County radon aggregate data →Measured Radon Data for Harrisburg
7 ZIP codes
17101 (Harrisburg), 17102 (Harrisburg), 17103 (Harrisburg), 17104 (Harrisburg), 17110 (Harrisburg), 17111 (Harrisburg), 17120 (Harrisburg)
These figures cover every test whose ZIP code is listed above. ZIP codes do not follow municipal lines, so the figures describe Harrisburg-area ZIP codes, not the municipal boundary of Harrisburg. They count tests, not homes.
Source: PA Department of Environmental Protection, Radon Test Results, data.pa.gov. Tests through July 2026. Retrieved September 29, 2026.
Ready to move forward? Talk to a DEP-certified pro.
Radon Mitigation Cost in Harrisburg
Active sub-slab depressurization (ASD) systems in Harrisburg typically cost $900–$2,300. Standard basement installs on modern poured concrete fall at the lower end; historic foundations, block-wall depressurization, multi-point suction, and crawlspace encapsulation push costs higher.
Foundations covered locally
- Basement (common in older homes)
- Slab-on-grade (newer suburbs)
- Crawlspace (rural areas)
Systems used in the region
- Active sub-slab depressurization
- Sump pit depressurization
- Passive venting systems
Certification & Compliance
All Pennsylvania radon testing and mitigation professionals must hold active PA DEP certification. Ask any contractor for their certification number and verify it before signing.
Pennsylvania's Real Estate Seller Disclosure Law (68 Pa.C.S. §§ 7301–7315) requires sellers to disclose known material defects to buyers under § 7303; the mandated disclosure form records radon under § 7304(b)(14). Sellers who have never tested are not compelled to test — § 7308 imposes no affirmative duty to investigate — but pre-listing testing is standard practice across most PA markets.
Under 25 Pa. Code § 240 — the Pennsylvania chapter governing radon certification — every radon service provider working in the Commonwealth must hold current DEP certification. Verify the contractor's status via the DEP Radon Services Directory before hiring.
Verify Contractor Certification — PA DEP Official Directory for Harrisburg, Dauphin County
View PA DEP Certified Contractor DirectoryThe PA Department of Environmental Protection maintains the official list of certified radon testers and mitigators, sorted by county and updated monthly. Always verify certification before hiring any contractor.
Directory resource provided by PA DEP Bureau of Radiation Protection, Radon Division.
Frequently Asked Questions
Is radon a significant risk in Harrisburg, PA?
Yes, though at lower rates than southeast PA. Harrisburg's Great Valley folded sedimentary geology — shale and sandstone ridges with limestone and dolomite valley floors — produces moderate radon concentrations. 53% of the 64,393 basement tests reported to PA DEP from Dauphin County measured 4.0 pCi/L or higher. DEP recommends testing all PA homes regardless of zone classification.
What does radon mitigation cost in Harrisburg?
Harrisburg area ASD systems typically cost $900–$2,300. Slab-on-grade homes common in newer Harrisburg suburbs may cost less to mitigate than full-basement colonial-style homes. Request quotes from DEP-certified Dauphin County contractors for property-specific pricing.
Do older Harrisburg neighborhoods have higher radon risk?
Generally yes. Pre-1980 homes in Harrisburg frequently lack vapor barriers and have porous concrete block or stone foundations, both of which permit greater radon intrusion from soil. Newer construction in surrounding suburbs typically has better passive protection, though active testing is still recommended.
What share of radon tests in Harrisburg-area ZIP codes are at or above the EPA action level?
49% of the 19,862 basement tests reported to PA DEP from Harrisburg-area ZIP codes measured 4.0 pCi/L or higher, 12 points above the 37% statewide share. The median result is 3.8 pCi/L. Of 4,806 first-floor tests, 29% measured 4.0 pCi/L or higher. The figures cover the ZIP codes listed on this page, not the municipal boundary, and they count tests, not homes.
Do homes in Harrisburg need to be tested for radon?
Dauphin County is EPA Zone 1 — the highest radon-potential classification — so every home in Harrisburg should be tested regardless of age, foundation type, or neighborhood. Short-term charcoal or continuous monitor tests take 48–96 hours and cost $15–$50; long-term alpha-track tests run 90 days and better represent annual averages. If the result meets or exceeds 4.0 pCi/L, mitigation by a DEP-certified professional is recommended.
How much does radon mitigation cost in Harrisburg?
Active sub-slab depressurization (ASD) systems in the Harrisburg area typically cost $900–$2,300. Standard basement installations on modern poured-concrete foundations fall at the lower end; historic foundations, block-wall depressurization, multi-point suction, and crawlspace encapsulation push costs toward the upper end. All work must be performed by a DEP-certified mitigation professional under 25 Pa. Code § 240.
Is radon disclosure required when selling a home in Harrisburg?
Pennsylvania's Real Estate Seller Disclosure Law (68 Pa.C.S. §§ 7301–7315) requires residential sellers to disclose known material defects to buyers (§ 7303). The state-mandated disclosure form covers 'presence of hazardous substances' at § 7304(b)(14) — where any known elevated radon test result or existing mitigation system is recorded. Sellers who have never tested are not required to test: § 7308 imposes no affirmative duty to investigate. In Harrisburg, the practical reality is that most buyers request radon testing during the inspection contingency period. Sellers who test and mitigate before listing eliminate the most common contract contingency and preserve negotiating position.
Which ZIP codes does the Harrisburg radon data cover?
The Harrisburg radon dataset on this page covers ZIP codes 17101, 17102, 17103, 17104, 17110, 17111, and 17120. These are the ZCTAs assigned to Harrisburg in the Census 2020 ZCTA-to-Place relationship file, and the page counts every test in the PA DEP record on data.pa.gov that carries one of them. A ZIP code can reach into a neighboring municipality, so the figures describe these ZIP codes rather than Harrisburg's municipal boundary.
Connect with a DEP-Certified Radon Pro in Harrisburg
Submit your request and we will connect you with a DEP-certified professional serving Dauphin County.
(717) 461-2427Connect with a DEP-certified radon pro