Radon Mitigation in Severance, Colorado | InspectandTest
Severance lies in EPA Radon Zone 1, the highest-risk category, where the predicted average indoor radon level meets or exceeds the 4 pCi/L action threshold. When a test in one of the town’s new finished-basement homes, in Hidden Valley, Tailholt, or Belmont Ridge, comes back elevated, mitigation is the engineered fix that brings the number down. Radon is a colorless, odorless radioactive gas and the second-leading cause of lung cancer after smoking. This page explains how radon mitigation severance homeowners should approach it, why local construction makes systems effective, and what the work costs. This summary reflects EPA and CDPHE guidance current as of 2026; consult a certified professional for mitigation decisions.
Radon mitigation in Severance: what to know
Radon mitigation is the installation of a system that reduces indoor radon to a safe level, almost always below the 4 pCi/L action threshold and ideally lower. The dominant method for Severance’s slab-on-basement homes is active sub-slab depressurization (ASD): a fan-powered pipe that draws soil gas from beneath the foundation and vents it above the roofline before it can enter living space.
The goal is not merely to dip under 4 pCi/L but to get the level as low as reasonably achievable, since the EPA notes there is no threshold below which radon carries zero risk. A well-designed system in a Severance home commonly brings a reading that started at 8 or 10 pCi/L down toward 1 to 2 pCi/L, close to typical outdoor air. Aiming for that lower target, rather than stopping just under the action level, gives the family the fullest protection in the finished-basement rooms where they spend the most time, and it provides a comfortable margin if conditions shift over the years.
Mitigation follows testing. A home should have a confirmed elevated reading before a system goes in, and it should be re-tested afterward to verify the fix worked. For how that initial measurement is done, see our guide to radon testing in Severance. The broader science of why Front Range homes accumulate radon and how reduction systems are designed is covered in our plain-language radon guide for Colorado homeowners.
Severance’s housing is well suited to mitigation. Most homes are recent builds with accessible slabs, sumps, and mechanical rooms, which makes routing an ASD pipe and finding a clean exterior or garage path straightforward. A new, tightly built home benefits even more, because once the depressurization system pulls soil gas away from the slab, the same air-tight envelope that trapped radon now helps keep it low.
It is worth distinguishing active mitigation from the passive measures sometimes confused with it. Sealing slab cracks, caulking the sump lid, or running an exhaust fan can nudge a borderline reading down, but on their own they rarely bring a genuinely elevated Severance basement below the action level reliably. The reason active sub-slab depressurization is the recommended fix is that it does not depend on sealing every possible entry point; instead it places the area under the slab at lower pressure than the home, so soil gas flows into the pipe rather than up through any crack the home develops over time. That is why an engineered, fan-powered system, not a patch-and-seal approach, is the durable answer to a high result.
Why Severance homes need radon mitigation
The need starts with geology. Radon comes from uranium decay in soil, and the northern plains soils around Severance release it readily, which is why all of Weld County sits in Zone 1. The actual indoor level depends on what lies directly under each foundation, so elevated results show up across new subdivisions regardless of how recently the home was built.
Construction style makes mitigation worthwhile precisely because it makes radon worse without it. Severance’s deep finished basements put bedrooms, offices, and family rooms in direct soil contact, and the tight, energy-efficient envelopes common in 2010s and 2020s builds limit air exchange so radon concentrates indoors. A finished basement that tests at 8 or 10 pCi/L is exposing the family in the most-used lower-level rooms, which is exactly the scenario sub-slab depressurization is designed to correct.
Climate compounds it through the heating season. Plains winters keep homes sealed for months while furnaces create negative pressure that draws soil gas upward through slab cracks and sump openings. A mitigation system reverses that pressure relationship under the slab, intercepting radon before it enters. The EPA estimates a properly installed system can cut indoor radon by up to 99 percent, which is why mitigation, not ventilation alone, is the recommended response to an elevated Severance result.
What Severance radon mitigation covers
A standard active sub-slab depressurization system is engineered to the specific home rather than installed from a template.
System design and installation
The installer cores a suction point through the basement slab, seals it, and runs PVC piping to an inline radon fan, typically mounted in the garage attic or on an exterior wall, that vents soil gas above the roofline. Existing sump pits are sealed and incorporated, slab cracks and the perimeter joint are caulked, and a visual pressure gauge (manometer) is installed so the homeowner can confirm the fan is running. In Severance’s newer homes, accessible slabs and clean utility runs usually allow a tidy installation.
Post-mitigation testing and verification
After the system runs for at least 24 hours, a follow-up radon test confirms the level has dropped below 4 pCi/L. Reputable installers include or recommend this verification, because a system that is installed but not confirmed has not actually solved the problem. Homes on the rural fringe with well water and high readings may also warrant a discussion of water-side radon, though sub-slab depressurization addresses the dominant soil-gas pathway. The EPA recommends re-testing every two years to confirm continued performance.
Radon mitigation cost in Severance
A typical active sub-slab depressurization system in the Severance market runs about $1,200 to $1,800 for a standard single-family home. Cost rises with complications, such as multiple suction points for a larger footprint, difficult routing in a fully finished basement, or a separate sump and drain-tile configuration that needs sealing.
Severance’s relatively uniform, recent housing stock tends to keep installations on the lower-to-middle end, because accessible slabs and clean mechanical paths reduce labor. Larger custom homes on acreage, or homes where the cleanest vent route runs through finished space, sit at the higher end.
Set the cost against the benefit. A one-time $1,500 system that takes a finished-basement reading from 9 pCi/L down near 1 pCi/L delivers a roughly 90 percent reduction in exposure for as long as the family owns the home, with only modest fan electricity and an occasional fan replacement over its life. Against the lung-cancer risk the EPA associates with long-term radon exposure, that is among the most cost-effective health improvements a Severance homeowner can make.
Colorado regulations and disclosure
Colorado requires radon disclosure in residential real-estate transactions, and the Seller’s Property Disclosure asks sellers to report known radon results and any existing mitigation system. CDPHE runs the state radon program and references the 4 pCi/L action level. Colorado does not license radon mitigators, so confirm any Severance installer follows national mitigation standards (such as ANSI/AARST) and provides post-mitigation verification.
For a sale, a documented mitigation system with a verifying post-test is a selling point: it shows the radon issue was identified and corrected to standard. A Severance seller who installs a system in Tailholt or Overlook should keep the installation paperwork, the manometer reading, and the confirming test, since that package reassures buyers far more than an unverified claim that radon “isn’t a problem here.” In a Zone 1 town, buyers increasingly expect either a clean test or a documented mitigation system.
Neighborhoods and areas served
Mitigation work in Severance concentrates in the finished-basement subdivisions, Hidden Valley, Tailholt, Belmont Ridge, and Overlook, where elevated Zone 1 readings most often surface, plus acreage homes on the agricultural fringe. Because the underlying plains geology is consistent across town, mitigation needs do not cluster in any one neighborhood; they follow wherever a test comes back high.
Service typically extends to adjacent plains communities in the same Zone 1 footprint, including Windsor, Eaton, Greeley, and Timnath. Severance homeowners can reference the county-level radon mitigation in Weld County hub for the regional picture, and those just west can read our companion guide to radon mitigation in Windsor. The engineering is the same across the area: depressurize the soil under the slab and vent above the roof.
Living with a radon system in a Severance home
Once an active sub-slab system is installed, it runs continuously and largely takes care of itself, but a few maintenance habits keep it performing for the life of the home. The radon fan is the only moving part, and it typically lasts somewhere in the range of five to ten years before the bearings wear out. When a fan fails it usually goes quiet rather than making noise, which is why the manometer, the small U-shaped gauge on the pipe, matters: a glance that shows the liquid levels offset means the fan is pulling suction, while a level reading means the fan has stopped and radon may be climbing again.
The system uses modest electricity, usually comparable to a couple of light bulbs running around the clock, a small ongoing cost against a large health benefit. Homeowners should avoid blocking or altering the vent pipe, and any future basement remodel should account for the system so a new wall does not bury the suction point or the manometer. If a Severance family finishes additional basement space after mitigation, a quick re-test confirms the system still covers the expanded footprint.
Re-testing is the other habit worth keeping. The EPA recommends re-measuring radon every two years and after any significant change to the home, a new furnace, a foundation repair, a basement finish, because those changes alter the pressure balance the system relies on. A Severance owner who watches the manometer, re-tests on schedule, and budgets for an eventual fan replacement gets decades of reliable protection from a one-time installation, turning a single fix into lasting peace of mind for the home’s most-used lower level.
How to choose a Severance radon mitigation provider
Choose an installer who follows ANSI/AARST mitigation standards, sizes the fan to the home, and includes a post-mitigation test to verify the result. A good provider explains the suction-point strategy, seals the sump and slab penetrations properly, and installs a visible manometer so you can confirm the system is working at a glance.
Ask about workmanship: a clean vent route, a fan rated for the home’s sub-slab conditions, and tidy sealing all signal a professional installation rather than a rushed one. Confirm whether the post-mitigation verification test is included or separate, and get the guaranteed result, a competent installer commits to bringing the level below 4 pCi/L. Pairing the work with a full home inspection in Severance can be efficient when radon surfaces during a purchase.
The mark of a trustworthy Severance mitigator is verification, not promises. A documented before-and-after, a guaranteed sub-4 result, and a system you can monitor yourself are what turn an elevated test into a solved problem for the life of the home.
References
- Consumer’s guide to radon reduction — U.S. Environmental Protection Agency
- Colorado radon program and mitigation guidance — Colorado Department of Public Health and Environment
- Radon health risk overview — Centers for Disease Control and Prevention
If a Severance radon test came back at or above 4 pCi/L, a properly engineered mitigation system can cut your exposure by up to 90 percent or more. To connect with a vetted local installer who verifies the result, reach out through our contact page.