Do I Need Radon Mitigation? A Homeowner's Decision Guide

Start With Your Number

The EPA's action level is 4 pCi/L. Above that, the agency recommends fixing your home. Below it, the risk is lower but not zero.

Here's how to think about your result:

Below 2 pCi/L — No action needed

This is a low result. The EPA outdoor average is 1.3 pCi/L, so you're not far above background levels. Retest in 2 years or if you do significant foundation work.

2–4 pCi/L — Your call, but lean toward mitigation

The EPA says "consider fixing." I'd be more direct: if you plan to live in this home for more than 5 years, seriously consider mitigation. The risk from 3 pCi/L over decades is real — it's just smaller than the risk above 4 pCi/L.

Mitigation at this level is the same cost and the same process as mitigation at 6 pCi/L. The only difference is the urgency.

Circumstances that push toward mitigation in this range:

• You have children or elderly family in the home
• You spend significant time in the basement
• You're in a high-radon state (Iowa, Pennsylvania, Colorado, Minnesota)
• You're planning to sell in the next 5 years

4–8 pCi/L — Mitigate

You're above the EPA action level. Get a certified mitigator. This isn't optional if you're living in the home long-term.

Timeline: Most contractors can schedule within 1–2 weeks. In high-radon states, some offer expedited scheduling for results in this range. The job itself takes one day.

What to expect: A standard sub-slab depressurization system will typically bring your levels below 2 pCi/L. Follow-up test in 24–48 hours confirms it worked.

8–20 pCi/L — Mitigate promptly

At this level, you're looking at meaningful cumulative lung cancer risk with years of exposure. Contact a certified mitigator this week, not next month. A standard system will usually handle this range, though the contractor may size up to a higher-suction fan.

Above 20 pCi/L — High urgency

Consider spending more time out of the home while arranging mitigation. At 20+ pCi/L, the contractor may need multiple suction points or a high-suction fan to achieve target levels. Budget for a slightly longer installation (still one day) and a follow-up test.

Do I Need to Retest Before Deciding?

Short answer: usually no, if you followed proper testing protocol.

A short-term charcoal test (48–96 hours) is accurate enough to make a decision. If you're genuinely borderline (3.5–4.5 pCi/L) and want confirmation before spending $1,000 on mitigation, a long-term alpha track test (90–365 days) gives you a more accurate annual average. Cost: $25–$35.

Situations where retesting makes sense:

• Your test was done during unusual weather (high winds, pressure changes)
• Your first test was in a season known for higher readings (winter in northern states)
• You want to verify a result that seems unexpectedly high or low for your area

Situations where retesting is NOT appropriate:

• You're above 8 pCi/L — the data is clear enough
• You're doing a real estate transaction with a deadline
• Your result was from a professional long-term test (already the gold standard)

What If My Neighbor Tested Fine?

Radon levels can vary dramatically from house to house on the same street — even from room to room in the same house. Your neighbor's result tells you nothing reliable about your home's level. Geology, foundation construction, soil permeability, and home tightness all create local variation.

One More Thing: The Fan Cost vs. Cancer Cost Math

A standard mitigation system runs $800–$2,500. It lasts the life of the home with a fan replacement every 5–15 years ($100–$250 for the fan).

Radon-induced lung cancer causes 21,000 deaths annually in the US. Treatment runs $150,000–$400,000+.

The math isn't close.

Find a certified mitigator in your state →