Apartment buildings and other multi-family properties raise a version of the radon question that single-family homeowners never have to deal with: one property owner, potentially dozens of separate households, and a mix of ground-floor units directly exposed to soil gas alongside upper-floor units that likely aren’t. This post covers how radon testing and mitigation work for apartments and multi-family housing in Pennsylvania. For the full picture of commercial radon across all building types, see our complete guide to commercial radon testing and mitigation in Pennsylvania.
Why Multi-Family Radon Is a Different Problem Than Single-Family Radon
A homeowner testing their own house is dealing with one foundation and one household. A landlord or property manager overseeing an apartment building, garden-style complex, or converted multi-unit property is dealing with several complicating factors at once:
- Ground-floor vs. upper-floor risk. Radon enters primarily through ground-contact surfaces, which means ground-floor and garden-level units carry meaningfully higher risk than units on the third or fourth floor of the same building — but tenants rarely know that, and a single building-wide answer (“we tested, we’re fine”) can be misleading if it was based only on an upper-floor unit.
- Landlord responsibility to multiple households. One elevated result affects every household in that unit, and potentially the units around it, which raises the liability stakes compared to a single owner-occupied home.
- Shared building systems. Many multi-family properties share HVAC risers, mechanical rooms, or ventilation systems across units, which can influence how radon moves (or doesn’t move) between spaces.
- Occupant turnover. Unlike a homeowner who might live in the same house for a decade, apartment tenants turn over regularly — which means testing needs to happen at the building or unit level, not rely on any single tenant to have ever raised the question.
Do Pennsylvania Landlords Have to Test for Radon?
Pennsylvania does not currently have a blanket statute requiring radon testing specifically for rental or multi-family housing, separate from the DEP’s certification requirements governing who is allowed to perform that testing. That said, the same liability logic that applies to any commercial building applies with extra weight here: a landlord is responsible for a habitable, reasonably safe living environment for tenants, and radon is a well-documented, inexpensive-to-rule-out health hazard. Property owners managing several units under one roof are also more exposed than a single-family homeowner simply because of the number of households potentially affected by one bad result.
How Testing Works Across a Multi-Family Property
Because risk concentrates at ground level, testing strategy for apartment buildings typically prioritizes:
- All ground-floor and garden-level units, tested individually rather than sampled.
- Common areas in contact with the ground — lobbies, laundry rooms, mechanical rooms, and below-grade storage.
- A representative sample of upper-floor units, particularly in buildings with shared vertical shafts or older construction where compartmentalization between floors may be weaker than in newer buildings.
Results are evaluated unit by unit and space by space against the EPA’s action level of 4.0 pCi/L, which gives ownership an accurate picture of exactly which units need attention rather than a single average that could mask a problem concentrated in a handful of ground-floor apartments.
Mitigation Systems for Apartments and Multi-Family Buildings
Mitigation approach depends heavily on construction type. A garden-style apartment complex with several separate slab-on-grade buildings often needs a dedicated sub-slab depressurization system per building, sized to that building’s footprint. A single larger apartment building over a shared basement or parking level may be mitigated more like an office building or institutional property — with sub-slab or sub-membrane suction addressing the ground-contact areas and coordination with any shared mechanical systems. In either case, the core engineering follows the same principles covered in our post on how commercial radon mitigation systems work, adapted to a property with multiple occupied households rather than a single tenant or owner.
A practical note for property managers: mitigation work in occupied apartment buildings needs to be scheduled and communicated carefully, since installation involves running piping through or near occupied units. A contractor with actual multi-family experience will plan installation to minimize disruption to tenants rather than treating the job like a single-family retrofit.
Budgeting for Multi-Family Radon Work
Costs for apartment and multi-family radon testing and mitigation scale with the number of buildings, units, and ground-contact zones on the property rather than following a single flat number — a four-unit garden building and a forty-unit complex are very different jobs. Our breakdown of commercial radon testing and mitigation costs in PA covers the specific factors that drive pricing for multi-family properties, so you can budget realistically before requesting quotes.
Who Pays, and How to Communicate with Tenants
Testing and mitigation costs for a multi-family property are almost always a landlord or ownership expense, the same as any other building system — heating, plumbing, or structural maintenance. Tenants generally aren’t expected to arrange or pay for radon testing in their own units, and property owners should be cautious about implying otherwise, since it can create the impression that the landlord is treating a building-wide safety question as an individual tenant problem. When testing does turn up an elevated result, straightforward communication works best: explain what was found, in plain terms tied to the EPA’s 4.0 pCi/L benchmark, and give a clear timeline for mitigation. Tenants are far more forgiving of an elevated result that’s being actively addressed than they are of silence.
For federally financed or subsidized multi-family properties, radon can also come up as part of broader indoor air quality expectations tied to financing or inspection programs — another reason to have current documentation on hand rather than scrambling to produce it during an inspection or refinance.
Protect Every Household in Your Property
Radon doesn’t announce itself, and in a multi-family property, one untested building can mean dozens of households living with an unknown risk. PA Radon Pros provides certified radon testing and mitigation for apartments and multi-family housing across Central Pennsylvania, from single garden-style buildings to larger multi-unit properties. Request a free quote or call us at (844) 945-4329 to get your property tested.
