PA DEP certificationMitigation #1725 · Testing #1725
Also offers: crawlspace sub-membrane depressurization, radon-resistant new construction and 2 morePost-mitigation radon testing in York County
Post-mitigation radon testing is the test after a radon system is installed. Pennsylvania's rules say the certified company that installs the system must make sure your home is tested. 4 PA DEP-certified companies in or near York County say on their websites that a retest comes with an install.
24 hoursEarliest start after the system is turned on
30 daysLatest the test can be done, unless something unforeseen stops it
48 hoursShortest test, with the system running
10 business daysTo get your written result
Which Radon Companies Do Post-Mitigation Testing in York County?
These PA DEP-certified companies say a retest comes with an install. Check where each is based and ask whether it serves your town.
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Sorted by number of Google reviews.
PA DEP certificationMitigation #2760 · Testing #2760
Also offers: continuous monitor testingPA DEP certificationMitigation #2691
PA DEP certificationMitigation #1800 · Testing #1800
What Is a Post-Mitigation Radon Test?
The test that checks a new radon system. PA DEP's mitigation fact sheet says it's the only way to know if the system is getting levels below 4 pCi/L.
Every install
Each building must be tested after the mitigation work (25 Pa. Code §§ 240.303 and 240.310).
Changes count too
The same timing rules apply after an alteration to an existing system.
Reported to DEP
The installer reports the job, the cost to you and the test result to DEP within 45 days of turning on the fan.
A test taken while a temporary radon reduction system is in use can't count as the post-mitigation test.
What Happens During a Post-Mitigation Radon Test?
The tester follows Pennsylvania's normal testing rules (25 Pa. Code § 240.310), with the system running the whole time. If it isn't working, you must be told right away.
Placement and the closed house follow the same rules as other tests. See continuous monitor testing and how to test. Within 10 business days you get a written Result Report Form, which includes:
- Each result in pCi/L, to one decimal place
- The exact start and stop dates and times
- The device's manufacturer, model and serial number
- The name and certification number of each tester
- The lab's name and certification number, if a lab analyzed it
- Whether a radon system was seen, and whether it was running
- Whether any tampering or change from test conditions was seen
This test isn't the last one. For DEP's advice on an independent test and when to retest, see is my radon system working?
What Should You Ask About the Post-Mitigation Test?
Who will do it, when, and whether the price guarantees a result below 4 pCi/L.
Who will do the test after the install?
The installer must make sure it's done, and may do it. DEP's consumer guide also recommends a test by an independent tester or by you.
When will it be done?
Between 24 hours and 30 days after the system is turned on, unless something unforeseen, such as the owner not letting the tester in, stops it.
What's the tester's PA DEP certification number?
Check it on PA DEP's Radon Services Directory, which DEP updates monthly, or ask to see a current DEP ID card.
Does your price guarantee a result below 4 pCi/L?
DEP's mitigation fact sheet says to check the written guarantee says so, and matches what you were told.
Common Questions About Post-Mitigation Radon Testing
Who does the post-mitigation test?
The installer must make sure it happens, and can do it. Someone else can do it too. If they do and you don't give the result to the installer, the installer doesn't have to report it to DEP.
Can the test be done the day the system goes in?
No. It can't start sooner than 24 hours after the system is finished and turned on.
Can I get a free follow-up test kit from DEP?
Possibly. PA DEP says that if a fan-powered system was installed in your home within the last year, you may get a free long-term test kit. Send DEP proof of the install and a post-mitigation result below 4 pCi/L. Allow 6 to 8 weeks.
Should the quote guarantee a result below 4 pCi/L?
Yes. PA DEP's fact sheet says to check the written guarantee is to get the home below 4 pCi/L for the quoted price.
Keep Reading About Radon Testing
Sources
- 25 Pa. Code § 240.303, Reporting of information
- 25 Pa. Code § 240.310, Testing protocols
- PA DEP: Pennsylvania Consumer's Guide to Radon Reduction
- PA DEP fact sheet: Radon Mitigation Systems (2940-FS-DEP4430)
- PA DEP: Radon in the Home
- PA DEP Radon Services Directory
Page last updated Oct 2026.