2026-01-20 · 5 min read
Radon Mitigation Cost in Maryland (2026): What to Expect
Maryland sits on the same Reading Prong geology as Pennsylvania — western and central counties routinely test above 10 pCi/L. Here's what mitigation costs by region in 2026.
Maryland Radon: A Piedmont and Appalachian Risk
Maryland's radon risk is geographically split. The western half of the state — from Frederick County through Washington County to Garrett County — sits on Appalachian and Reading Prong geology with uranium-bearing rock. These areas regularly test at 8–20+ pCi/L.
The DC suburbs (Montgomery, Howard, Carroll counties) also run high, driven by Piedmont crystalline rock formations. Eastern Shore counties (Talbot, Dorchester, Somerset) are Zone 2 or 3 — still worth testing, but lower risk.
Maryland is one of the few states that licenses radon contractors. MDE licensing is required in addition to NRPP or NRSB certification. Always verify both credentials before hiring.
Maryland Average Costs by Foundation Type
| Foundation Type | Typical Range | Notes |
| Basement | $950–$2,000 | Very common in MD — especially older suburbs |
| Slab-on-grade | $900–$1,800 | Common in newer construction |
| Crawl space | $1,400–$3,000 | Vapor barrier often required |
| Block wall foundation | $1,200–$2,400 | Common in older homes — requires sealing |
Regional Price Breakdown
Washington DC Suburbs (Montgomery, Prince George's, Howard Counties)
The most expensive Maryland market due to high labor costs and strong real estate activity.
- Sub-slab depressurization: $1,100–$2,200
- Typical average: $1,400–$1,700
Frederick / Carroll / Washington Counties
High-radon zone with moderate contractor supply. Strong demand keeps pricing competitive.
- Sub-slab depressurization: $950–$1,800
- Typical average: $1,200–$1,500
Western Maryland (Allegany, Garrett Counties)
Highest-risk region in the state. Limited contractor density can push prices up.
- Sub-slab depressurization: $1,000–$2,000
- Travel fees: $75–$200 common in rural areas
Eastern Shore (Talbot, Dorchester, Wicomico)
Lower radon risk but still worth testing. Fewer contractors — prices vary widely.
- Sub-slab depressurization: $900–$1,700
What Drives Costs Higher in Maryland
Block wall basements: Many older Maryland homes (1950s–1980s) were built with concrete block foundations. Block walls require sealing to prevent radon entry through the wall itself — adding $300–$600 to standard jobs.
Finished basements: Baltimore and DC suburb homes often have fully finished basements used as living space. Routing pipe through finished walls adds labor and may require drywall patching.
State licensing requirement: Maryland's MDE license requirement filters out the lowest-cost (and often least qualified) contractors. This is a good thing for consumers, but it does keep floor prices slightly higher than unlicensed states.
Maryland's Radon Contractor Licensing
Maryland requires radon mitigators to hold a state license from the Maryland Department of the Environment in addition to national certification. To verify:
- Ask the contractor for their MDE license number
- Verify at mde.maryland.gov (Radon Contractor List)
- Verify NRPP at radonproficiency.org or NRSB at nrsb.org
Maryland Resources
- Maryland Department of the Environment Radon Program: mde.maryland.gov/radon or 410-537-3491
- Verify MDE license: mde.maryland.gov
- Verify NRPP: radonproficiency.org
- Verify NRSB: nrsb.org
Frequently Asked Questions
How bad is radon in Maryland?
Western Maryland (Garrett, Allegany, Washington counties) and parts of the Piedmont (Frederick, Carroll, Howard, Montgomery) are among the highest-testing areas in the Mid-Atlantic. The EPA places most of western and central Maryland in Zone 1 — the highest risk category. An estimated 40% of Maryland homes in these zones exceed 4 pCi/L.
How much does radon mitigation cost in Maryland?
Most Maryland homeowners pay $900–$2,200 for a standard sub-slab depressurization system. The DC suburbs (Montgomery, Prince George's, Anne Arundel) trend toward the higher end due to labor costs. Western Maryland and rural areas are more moderate.
Does Maryland require radon disclosure in real estate?
Maryland law requires sellers to disclose "known" radon levels under the Residential Property Disclosure Act. In practice, buyers should always request an independent radon test — a seller disclosure of "unknown" doesn't mean the home is safe.
Does Maryland license radon contractors?
Maryland requires radon mitigators to be licensed through the Maryland Department of the Environment (MDE). Look for an MDE Radon Contractor license in addition to NRPP or NRSB certification.
Find a Certified Mitigator Near You
Every contractor on RadonBase is NRPP or NRSB certified — mitigators only, no testers.
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