Statewide Wisconsin Realtor Resources
Wisconsin Real Estate Radon Resources
Statewide radon testing and mitigation support for Wisconsin realtors, brokers, and MLS members. Closing-timeline turnarounds, Wis. Stat. § 709.03 Form WB-3 disclosure compliance, and NRPP- or NRSB-certified partner contractors across 14 Wisconsin cities — with credential verification done for you.
Wisconsin Radon Disclosure Law for Real Estate Transactions
Wis. Stat. § 709.03 governs Wisconsin residential real estate disclosure through the Real Estate Condition Report (RECR), commonly known as Form WB-3. Sellers are required to disclose any known prior radon testing or installed mitigation system as part of the standard RECR. The disclosure must be provided to the buyer within 10 days of accepting an offer. While Wisconsin does not legally mandate pre-sale testing, the Wisconsin REALTORS Association references radon testing as standard practice given the state's elevated geological background — particularly in the 26 EPA Zone 1 counties and in Wausau-area homes on Precambrian granite.
Key disclosure requirements under Wisconsin law:
- If radon testing has been performed at the property, the seller must disclose the date and result on the RECR.
- If a radon mitigation system is installed, the seller must disclose the installation date and any verification testing results.
- Sellers cannot legally withhold known radon information about the property.
- Penalties for failing to disclose known radon issues may include rescission of the sale and damages.
- Note: Wisconsin has NO state-level licensing or registration requirement for radon contractors — the seller's disclosure should reference NRPP or NRSB national certification number of the installing contractor for buyer credential verification.
The Wisconsin REALTORS Association recommends including a radon contingency clause in every Wisconsin Residential Offer to Purchase (Form WB-11), allowing buyers to: (1) conduct radon testing during the inspection period, (2) require seller mitigation if results exceed 4 pCi/L, (3) negotiate cost responsibility, and (4) terminate the agreement if mitigation cannot be completed within the closing timeline.
Wisconsin Real Estate Radon Transaction Timeline
Standard Wisconsin transaction timeline from initial test through verified post-mitigation result, designed to fit within most inspection contingency windows.
| Day | Step | Who | Duration |
|---|---|---|---|
| Day 0 | CRM deployed at property during home inspection | Inspector / mitigation specialist | Instantaneous |
| Day 2-4 | Test retrieval + result reporting | Inspector / mitigation specialist | 48-96 hr test period |
| Day 4 | Result review — elevated (>4 pCi/L) triggers mitigation | Realtor + buyer + seller | 1 day |
| Day 5-7 | On-site assessment by NRPP/NRSB-certified mitigator | Partner contractor | 1-2 hr visit |
| Day 7-9 | Written quote provided + cost negotiation | Realtor + buyer + seller | 2-3 days |
| Day 9-12 | Mitigation system installed | Partner contractor | 4-8 hours on-site |
| Day 13-16 | Post-mitigation verification test (WI DHS recommends within 30 days) | Partner contractor | 48-96 hr test |
| Day 16 | Verification result + final documentation | Partner contractor | 1 day |
| Day 16+ | Closing proceeds with verified mitigation | Closing agent | Per contract |
Services We Provide to Wisconsin Realtors
- Pre-listing radon testing — Recommend to sellers before MLS listing to surface and mitigate radon issues upfront. Particularly valuable in Driftless Area counties, Marathon County (Wausau), and Dane County (Madison) where elevated readings are common.
- Pre-purchase radon testing — Buyer-side testing during inspection contingency period. CRM-based for transaction-grade documentation.
- Closing-timeline mitigation — Expedited 7-14 day install + verification turnaround. Designed for active transactions.
- Existing system verification — Confirms that a previously-installed radon mitigation system is still maintaining indoor radon below 4 pCi/L. Standard practice for transfers of homes with existing systems, especially on Driftless karst and Precambrian granite substrates.
- Licensed child care center compliance — Mandatory testing and mitigation per Wis. Admin. Code § DCF 250.06(6)(a). Wisconsin's only mandatory radon testing law — important for realtors marketing licensed child-care-zoned commercial properties.
- FHA / USDA / VA loan compliance documentation — Test reports and verification documentation in lender-acceptable formats.
- NRPP/NRSB credential verification — Wisconsin has no state contractor registry, so we verify every partner contractor's national credentials directly. Realtors get credential documentation for the closing file.
- Multi-property portfolio testing — Wisconsin property managers, REITs, and rental portfolio owners.
Wisconsin MLS Coverage Areas
Wisconsin Radon Experts partner network serves the major Wisconsin MLS regions:
- Greater Milwaukee Association of Realtors (GMAR) — Milwaukee, Waukesha, Racine, Kenosha, West Allis, plus Milwaukee/Waukesha/Ozaukee/Washington counties
- South Central Wisconsin Realtors — Madison, Dane County, Janesville/Rock County corridor
- Realtors Association of Northeast Wisconsin (RANW) — Green Bay, Appleton, Oshkosh, Sheboygan, Fox Valley region
- Greater Northwoods Multiple Listing Service — Wausau, Marathon County, northern Wisconsin
- Western Wisconsin REALTORS Multiple Listing Service — Eau Claire, La Crosse, Driftless Area
- Wisconsin REALTORS Association (statewide) — wra.org, statewide trade association
Statewide partner contractor coverage available for properties outside the 14 directly-served cities.
Realtor FAQ
Wisconsin Real Estate Radon Questions Realtors Ask
Frequently Asked Questions
Does Wisconsin law require radon testing before a home sale?
Wisconsin does not legally require pre-sale radon testing, BUT Wis. Stat. § 709.03 requires the seller's Real Estate Condition Report (Form WB-3) to disclose any known prior radon testing or installed mitigation system. The disclosure must be provided to the buyer within 10 days of accepting an offer. In practice, most Wisconsin real estate transactions now include a radon contingency clause in the purchase agreement, and the Wisconsin REALTORS Association references radon testing as standard practice. Many lenders — particularly FHA-backed loans in Wisconsin's 26 EPA Zone 1 counties — increasingly request radon testing as a condition of loan approval.
What is the standard radon testing protocol for Wisconsin real estate transactions?
For real estate transactions, EPA recommends a short-term test (48-96 hours) using either a charcoal canister or continuous radon monitor (CRM) under closed-house conditions. The CRM method is preferred for transactions because it provides hour-by-hour readings that can detect tampering (windows opened during the test) and supplies a defensible time-stamped result for closing documentation. Wisconsin Radon Experts partner contractors use AARST-NRPP-certified Femto-TECH and Sun Nuclear CRMs for all transaction testing.
If a radon test comes back elevated, can mitigation be completed before closing?
Yes. Standard Wisconsin real estate transaction radon mitigation timeline: Day 0 — test result received (elevated, >4 pCi/L); Day 1-3 — partner contractor on-site assessment; Day 3-5 — written quote provided; Day 5-7 — buyer/seller agreement on cost responsibility; Day 7-10 — mitigation system installed (typically 4-8 hours of on-site work on a standard glacial-till basement; Wausau-area Precambrian granite homes with high pre-readings may need higher-capacity fans); Day 11-14 — post-mitigation verification test conducted; Day 14 — final report ready for closing documentation. The full cycle typically takes 7-14 days. WI DHS recommends verification testing within 30 days of system activation.
Who typically pays for radon mitigation in a Wisconsin real estate transaction?
Across Wisconsin transactions, cost responsibility is negotiated between buyer and seller after an elevated test result — the Wisconsin WB-11 Residential Offer to Purchase does not mandate which party pays. Roughly half of Wisconsin mitigations are seller-paid; the remainder are negotiated cost-shares, closing credits, or buyer-paid. Many Wisconsin listing agents now recommend pre-listing radon testing so sellers can mitigate proactively or price-adjust before listing, avoiding mid-transaction disputes — particularly important in high-radon counties like Dane (Madison), Marathon (Wausau), and the Driftless Area counties.
Are FHA loans different on radon requirements in Wisconsin?
HUD Handbook 4000.1 does not require radon testing for FHA-backed loans as of 2026, but HUD strongly encourages radon testing on all FHA-insured properties. Wisconsin's 26 EPA Zone 1 counties (including Dane/Madison, Waukesha, Rock/Janesville, Marathon/Wausau, and the Driftless Area counties) frequently prompt FHA underwriters to request radon test results during underwriting, and many Wisconsin FHA lenders include radon testing as part of standard inspection requirements. USDA Rural Development loans similarly encourage testing — relevant for the substantial rural Wisconsin transaction volume. VA loans do not require radon testing but VA appraisers may flag elevated radon as a property condition issue.
Can radon testing be done at the same time as a home inspection?
Yes, and this is the standard Wisconsin practice. Most Wisconsin home inspectors place a continuous radon monitor (CRM) during the inspection and retrieve it 48-96 hours later when they return for the final inspection report walkthrough. Some inspectors are certified to provide radon testing themselves; others coordinate with NRPP- or NRSB-certified partner companies like the Wisconsin Radon Experts network. Coordinating testing with inspection compresses the transaction timeline.
Does an existing radon mitigation system need to be tested before transfer of ownership?
Best practice — yes. Post-mitigation verification testing whenever a home with an existing radon system changes ownership confirms the system is functional and currently maintaining indoor radon below the EPA action level of 4 pCi/L. Many Wisconsin real estate transactions include verification testing of existing systems as a buyer-protection step. If the seller cannot produce documentation of the original mitigation install plus regular biannual testing, buyers commonly request a current verification test as a condition of closing. This is especially important on Driftless Area karst substrates and Precambrian granite foundations where soil-gas pathways can shift seasonally.
Wisconsin MLS — how should radon mitigation be disclosed in listing notes?
Wisconsin MLS listings should disclose: (1) Whether radon testing has been performed and the date + result, (2) Whether a radon mitigation system is installed and the installation date, (3) Date of the most recent post-mitigation verification test and the result, (4) The contractor who installed the system — Wisconsin has no state license, so the listing should reference NRPP or NRSB certification number for buyer credential verification. Sellers who have proactively tested and mitigated typically command faster offers and higher closing prices because radon uncertainty is removed from buyer negotiations. The Wisconsin REALTORS Association supports full radon disclosure on Wisconsin MLS listings.
How does Wisconsin Radon Experts work with real estate agents?
Wisconsin Radon Experts is a lead-routing service that connects realtors and their clients with NRPP- or NRSB-certified partner contractors statewide. Realtors can request testing or mitigation services directly through our contact form or by calling our routing line. Standard turnaround: response within 4 business hours, on-site visit within 2-7 days, post-mitigation verification testing included. We do not pay referral fees — Wisconsin real estate law prohibits paying real estate licensees for unlicensed work referrals. We do provide expedited closing-timeline scheduling at no premium for licensed Wisconsin realtors, plus pre-verified NRPP/NRSB credentials (work that Wisconsin's no-state-license environment normally puts on the realtor or buyer).
Wisconsin Realtor? Set Up a Direct Partnership Line.
Realtors get expedited routing, transaction-grade documentation, pre-verified NRPP/NRSB credentials, and direct partner contractor access for every Wisconsin listing. Call TODO_RESEARCH: Google Voice with WI area code (608 Madison / 414 Milwaukee / 920 Green Bay) or submit a quote request.