Free Colorado Radon Gas Disclosure

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Free Colorado Radon Gas Disclosure — overview

A Colorado Radon Gas Disclosure documents the landlord’s knowledge of radon test results and mitigation status for the rental property at the time of lease signing. Colorado has among the highest indoor radon levels in the United States. The EPA action level for radon is 4.0 pCi/L; Colorado’s average is approximately 6.3 pCi/L. The form on this page produces a signed disclosure that becomes part of the lease record.

Complete the Disclosure Form

Complete the form below to generate a comprehensive Colorado Radon Gas Disclosure. The form produces a multi-page PDF in legal-document format with all sections, signature lines, and tenant acknowledgment. Both parties should sign the printed copy.

About Colorado Radon Gas Disclosure

Colorado is consistently ranked among the states with the highest indoor radon levels in the nation. Radon is a naturally occurring, colorless, odorless radioactive gas that forms from the decay of uranium in soil and rock. It is the second-leading cause of lung cancer in the United States after smoking.

Colorado’s Radon Profile

• Colorado average indoor radon level: approximately 6.3 pCi/L
• EPA action level: 4.0 pCi/L — Colorado’s average is about 57% above this threshold
• More than 50% of Colorado homes test above the EPA action level
• Higher-risk areas include the Front Range, Colorado Springs, and many mountain communities

Mitigation Reduces Risk Substantially

A properly installed sub-slab depressurization (SSD) system typically reduces radon levels by 80-99%. If your property tests at or above 4.0 pCi/L, mitigation is a worthwhile investment in tenant health and landlord liability protection.

Related Resources

• Colorado habitability laws
• Colorado landlord tenant laws
• Colorado tenant screening laws
• Colorado security deposit laws
• Colorado eviction notice laws
• Habitability laws by state

Does Colorado law actually require a landlord to disclose radon?

Yes. C.R.S. § 38-12-803 requires a Colorado landlord to make a written radon disclosure before the tenant signs the lease agreement, in a document the tenant signs to acknowledge receipt. The section was added by SB 23-206, effective August 7, 2023, and its definition of “residential real property” covers a single-family home, manufactured home, mobile home, condominium, apartment, townhome, or duplex.

Three things must be delivered together under C.R.S. § 38-12-803(2)(a):

• The statutory warning statement, in bold-faced, clearly legible type, in substantially the form the statute sets out — the paragraph beginning “The Colorado Department of Public Health and Environment strongly recommends that ALL tenants have an indoor radon test performed.” Reproduce it; do not paraphrase.
• Everything the landlord knows about the property’s radon concentrations — whether any test has been conducted, the most current records and reports, a description of any concentrations detected and any mitigation or remediation performed, and a description plus documentation of any installed radon mitigation system.
• A copy of the most recent brochure published by the Colorado Department of Public Health and Environment under C.R.S. § 25-11-114(2)(a) giving advice about radon in real estate transactions. The statute says “most recent,” so pull the current edition from CDPHE rather than reusing an old copy.

Does the duty apply to renewals?

The trigger in C.R.S. § 38-12-803(2)(a) is signing a lease agreement, and the section carries no exception for renewals, existing tenants, or a property disclosed on once already. Treat the disclosure as due again before any renewal executed as a new signed lease: the packet rides with every lease signature, not just first move-ins.

Must a Colorado landlord test for radon?

No. Colorado requires disclosure of what the landlord knows, not testing. C.R.S. § 38-12-803 imposes no duty to order a radon test, and subsection (2)(a)(II) asks only for “any knowledge the landlord has” of the property’s radon concentrations. A landlord who has never tested discloses that no test has been conducted, delivers the warning statement and the CDPHE brochure, and has complied.

Mitigation is conditional in the same way. There is no free-standing duty to remediate, but C.R.S. § 38-12-803(3)(a)(II) attaches a consequence: once a radon measurement professional determines the air concentration is four picocuries per liter or more and the landlord is notified, the landlord has 180 days to make a reasonable effort to mitigate. Four pCi/L is the only numeric level named in the section.

What is the tenant’s remedy if the disclosure is missing?

Under C.R.S. § 38-12-803(3)(a), a tenant may void the lease agreement and vacate the premises in accordance with C.R.S. § 38-12-507 if the landlord failed to provide the written disclosures, or failed to mitigate within the 180-day window above. Subsection (3) names no civil penalty and no statutory damages figure.

Two qualifications matter, and they cut in opposite directions:

• The short-lease carve-out. C.R.S. § 38-12-803(3)(b) provides that on or after January 1, 2026, subsection (3) does not apply to a lease agreement one year or less in duration. By its own terms it limits only subsection (3) — the disclosure duty in subsection (2) is untouched.
• The habitability hook. C.R.S. § 38-12-505(1)(b)(XV) deems a residential premises uninhabitable if it substantially lacks “compliance with all requirements in section 38-12-803,” and C.R.S. § 38-12-505(3)(b) provides that a landlord leasing a premises out of compliance with that section breaches the warranty of habitability under C.R.S. § 38-12-503(1), with the tenant able to pursue any remedy under C.R.S. § 38-12-507. Neither provision carries the one-year carve-out.

Recordkeeping

Keep the tenant-signed acknowledgment past the end of the tenancy. That signature is the proof C.R.S. § 38-12-803(2)(b) requires and the only practical way to rebut a claim that nothing was delivered. File with it the CDPHE brochure edition you handed over, any test reports disclosed, and the mitigation documentation. Date-stamp any notification of a professional test at or above four picocuries per liter — the 180-day clock runs from the day you were notified.

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