About Wisconsin Radon & Environmental
Built on One Simple Principle: Do the Job Right
Wisconsin Radon & Environmental, LLC was founded on a straightforward idea — that homeowners and property owners dealing with radon or environmental concerns deserve a contractor who actually knows what they’re doing, takes the work seriously, and doesn’t leave until the job is done right. That’s not a marketing line. It’s how we’ve operated for over 15 years, and it’s why more than 314 Wisconsin clients have left us a five-star review
15
Years Experience
314
Five-Star Reviews
A
Five-Star Reviews
NRPP
Five-Star Reviews
Meet Jerome O’Callaghan, Founder
Jerome O’Callaghan started Wisconsin Radon & Environmental after seeing a consistent gap in how radon and environmental services were being delivered across Southeast Wisconsin. Property owners were hiring companies that sent out crews without adequate oversight and used subcontractors without proper certification.
Jerome set out to build something different — a company grounded in technical expertise, transparent communication, and a genuine commitment to results.
As founder, Jerome remains deeply hands-on across every aspect of our work. His direct involvement in every project ensures that the standard of care our clients expect is consistently delivered — whether it’s a single-family radon mitigation or a complex commercial vapor intrusion assessment.
Certifications & Credentials
Radon Mitigation
residential and commercial
Radon Measurement
residential and commercial
Multifamily Radon Measurement
apartment buildings and multi-unit properties
Radon Mitigation in Schools and Large Buildings
institutional and commercial scope
We maintain an A+ rating with the Better Business Bureau and have earned 314+ five-star reviews on Google across 15+ years of service in Southeast Wisconsin.
We are fully insured and operate in compliance with all Wisconsin Department of Health Services radon program
guidelines
What We Do
Our core services:
Radon Mitigation System Installation
We design and install Active Soil Depressurization (ASD) systems custom-engineered for your property’s specific foundation type, soil conditions, and construction. Most residential installations are completed in a single day
Radon Testing & Measurement
Short-term and long-term NRPP-certified radon testing for homeowners, real estate buyers and sellers, landlords, and commercial property owners
VOC & Vapor Intrusion Mitigation
We assess and mitigate indoor air quality threats from Volatile Organic Compounds (VOCs), including chlorinated solvents such as PCE (perchloroethylene) and TCE (trichloroethylene),
as well as petroleum-based hydrocarbons including benzene, toluene, and other BTEX compounds. These contaminants enter buildings through the same pathways as radon and require the same technical expertise to properly address. We serve residential homeowners, commercial property owners, real estate professionals, and clients navigating brownfield redevelopment and environmental due diligence
Our Industry-Leading Guarantee
Most radon contractors guarantee only the EPA’s 4.0 pCi/L action level. We don’t consider that a complete result — it’s a starting point. Every Wisconsin Radon & Environmental standard installation is guaranteed to bring your home below 2.7 pCi/L — the World Health Organization’s recommended threshold. That alone puts us well ahead of most competitors before we even discuss our premium tier.
For homeowners who want the absolute highest level of protection, our premium guarantee tier targets below 1.5 pCi/L — an industry-leading standard that very few contractors in the country offer. It requires more precise system design and a higher level of technical execution, and it delivers the best radon reduction result available. On both tiers, if your post-mitigation test doesn’t meet the guaranteed threshold, we come back and make it right. That’s our commitment on every job
Serving Southeast Wisconsin
Wisconsin Radon & Environmental serves homeowners, real estate professionals, landlords, and commercial property owners throughout Southeast Wisconsin, including Milwaukee, Waukesha, Ozaukee, Washington, Racine, and Kenosha counties, and communities working south toward the Illinois border. We are locally owned, locally operated, and deeply committed to this region. This is our community. We live and work here, and we take the health of Wisconsin homes and properties personally
Ready to Get Started?
Whether you’re dealing with radon, concerned about chemical vapors, or navigating a real estate transaction with an environmental contingency — we’re here to help
Wisconsin Radon & Environmental, LLC
1155 N 21st St
Milwaukee, WI
53233
