Warren County, NJ radon levels: test-to-decision path
Fast county answer: If you landed here from a Warren County radon-level search, start with the short lane: no reading yet, borderline result, or 4.0+ result. Warren County is a near-miss county from the search data. Keep the path short: first test, retest a borderline result, or price a confirmed 4.0+ result.
Keep the county path short
These counties already showed search traction. The page now removes the extra step between county evidence and the next action.
Near-miss search signal: keep the page focused on the next practical decision.
No reading yet means test first. Borderline means retest. 4.0+ means cost or credit planning.
Pick one route now: test, retest, local cost, or seller-credit math.
Official County Evidence
Warren County evidence before the next step
Warren County, NJ has more than the EPA map: NJ DEP exposes municipality radon potential tiers, with 100.0% Tier 1 and 100.0% Tier 1 or Tier 2 municipalities.
Source window
Current source summary
County evidence type
High radon-potential area
County context only; your home test controls the decision.
Primary result
Tier 1 dominant
n/a in-state
4.0+ signal
100.0% Tier 1
n/a in-state
High-end signal
Tier 1 present
n/a in-state
Official evidence dossier
Source record for Warren County, NJ
NJ DEP publishes municipal radon-potential tiers, so this county is interpreted from local tier concentration rather than a county pCi/L average.
Primary public source
NJ municipal radon-potential table
Measurement window
Current source summary
Retrieved / checked
See source
County FIPS
34041
Evidence stack
County source
NJ municipal radon-potential table
Primary source used for the county evidence row.
Federal map
EPA Map of Radon Zones
Zone 1 is context, not a property result.
Housing context
US Census ACS housing context
38.9% built before 1980; 46,493 housing units.
State follow-up
State radon program
Use the state source before hiring or interpreting local rules.
Primary field
Tier 1 dominant
Median field
Not available
4.0+ field
100.0% Tier 1
Sample / volume
22 municipalities
Metric shape
This uses the share of Tier 1 and Tier 2 municipalities. Treat it as a reason to test, not as a home reading.
Source limitation
This county context cannot diagnose a specific property. Use it to choose the right test and official follow-up path.
Property-level limit
Not a property-level diagnosis. The county record explains local evidence; your home's own test result controls the next decision.
County-specific interpretation
Warren County, NJ is interpreted from NJ municipal radon tiers, not a county average.
Warren County is a test-now case because the NJ DEP table shows 100.0% Tier 1 and 100.0% Tier 1 or Tier 2 municipalities. No reading means get the first number; a 4.0+ result should move into mitigation quotes.
Real-estate use
Buyer or seller use: ask for a fresh lowest-level test before inspection deadlines, tie any 4.0+ result to a contractor quote, and do not negotiate from the county signal alone.
Warren County should be treated as an NJ tier-heavy county: test before purchase or renovation decisions, and move any 4.0+ result into mitigation pricing.
Use This EvidenceOfficial state path
Open the state radon program
Use state rules and local program contacts before choosing a contractor.
EPA hiring guidance
Find a qualified radon provider
EPA points homeowners to state programs and national proficiency listings.
Certified professional search
Search NRPP-certified pros
Use this after you have a valid result or need professional testing.
Testing priority answer
Is Warren County a higher-priority radon testing county?
Warren County is not shown from a county average table here; it is interpreted from NJ DEP municipal tier distribution. Treat Tier 1/Tier 2 concentration as a test-priority signal, then let the home result decide mitigation.
Enter the result. Pick the deal side. Get the route.
Near-miss search signal: keep the page focused on the next practical decision.
County signal
Not available
At or above 4.0
Not available
Decision side
Foundation clue
Choose your next step
Start from the exact job, not another generic radon article.
Pick the situation that matches Warren County, NJ. Each route keeps the reading, deal side, or foundation clue attached so the next page answers the search instead of resetting the user.
Failed inspection
I need a repair or seller credit number
Open the local credit path with a 4.0+ buyer scenario already selected.
Open negotiation route4.0+ pCi/L
I have a high result and need the cost path
Go straight to the county estimate, quote context, and contractor checklist.
Open cost route2.0-3.9 pCi/L
I need to know if this number is bad
Use the level explanation first, then decide whether to retest, monitor, or price mitigation.
Open level routeNo test yet
I need the first valid result
Start with kit placement, timing, closed-house conditions, and result interpretation.
Open testing routePick the situation that matches you
You should not need to read the whole guide before clicking one of these. Start with the lane that matches your current stage, then come back for the deeper reference only if you still need it.
Use the Warren County short path first; the deeper source detail is below if you need it.
I have not tested yet
Do not price mitigation blind. Get the first number, then decide whether you need monitoring, quotes, or nothing at all.
My result is 2.0-3.9
Usually confirm the reading first. If it keeps showing up, use the county evidence and official guidance before deciding whether pricing makes sense.
My result is 4.0+
This is the EPA action line. Use the local cost page before calling contractors so you know the likely scope, timing, and budget.
I am buying or selling
Turn the reading into a credit or repair number before negotiation starts. This is the faster path than arguing from a generic article.
Already tested once and need the cleanest follow-up path?
Review retesting stepsNear-Miss County Playbook
This county gets the short route first.
Search Console already showed enough signal to keep this page focused. The fastest useful answer is whether the visitor needs a first test, a retest, a local cost range, or seller-credit math.
County Evidence Snapshot
Warren County testing context
Warren County should be treated as a testing-priority county because the official source signal backs up the EPA high-zone warning. The NJ DEP tier table makes this a testing-priority county; use the tier signal to prioritize a home test, not as a home reading. Use the EPA map as context, but let the home test decide mitigation or credit planning.
EPA map signal
Zone 1
County-level predicted indoor screening range, not a home-level test result.
Housing base
46,493
10th percentile among 21 NJ counties with data.
Older housing share
38.9%
57th percentile in-state; older homes often need clearer test placement decisions.
Median home value
$302,300
Used as context for whether mitigation is a small maintenance item or a negotiation issue.
County evidence interpretation
High radon-potential area
Primary result rank
n/a
Tier 1 dominant
4.0+ rank
n/a
100.0% Tier 1 at or above 4.0
High-end rank
n/a
Tier 1 present
Test volume rank
n/a
22 municipalities
How to use this county data
Data source
NJ municipal radon-potential table
NJ DEP publishes municipal radon-potential tiers, so this county is interpreted from local tier concentration rather than a county pCi/L average.
What the numbers show
Town-level radon potential
This uses the share of Tier 1 and Tier 2 municipalities. Treat it as a reason to test, not as a home reading.
Nearby comparison
Nearby comparison: compare NJ counties by Tier 1 and Tier 1-or-2 municipal share, then let the home test decide action.
How this helps
Use this when deciding whether to prioritize testing before purchase, renovation, or a retest.
What the data says
Warren County, NJ has 22 Tier 1 municipalities, 0 Tier 2 municipalities, and 0 Tier 3 municipalities in the NJ DEP radon potential table.
100.0% of municipalities are Tier 1 and 100.0% are Tier 1 or Tier 2. This is a reason to prioritize testing, not a county average pCi/L measurement.
What to do with it
Warren County should be treated as an NJ tier-heavy county: test before purchase or renovation decisions, and move any 4.0+ result into mitigation pricing.
Retest trigger: a 2.0-3.9 pCi/L home result should be confirmed when local NJ tier concentration is meaningful; the tier table is a priority signal, not a home result.
Source-backed context from NJ DEP municipality-level radon potential designations; numeric county pCi/L metrics are still not normalized.
No reading yet
No reading yet: use the NJ tier signal to prioritize testing, but do not treat a tier as a home result.
2.0-3.9 result
2.0-3.9 pCi/L: retest or track; tier context can justify not dismissing a borderline result.
4.0+ result
4.0+ pCi/L: move to mitigation quotes or seller-credit planning; the home result outranks the tier map.
Source hierarchy: NJ DEP radon potential tiers are used for this county, with EPA zone and Census housing data as supporting context.
Direct Answer
Is Warren County a higher-priority radon testing county?
Warren County is not shown from a county average table here; it is interpreted from NJ DEP municipal tier distribution. Treat Tier 1/Tier 2 concentration as a test-priority signal, then let the home result decide mitigation.
| Evidence | Value |
|---|---|
| Area | Warren County, NJ |
| EPA Zone | Zone 1 |
| Primary Recommendation | Perform direct radon testing in the lowest livable level |
Your Radon Reading
Enter your home's measured level. The county evidence is a radon-potential tier, not a pCi/L reading.
Warning: Action Required - EPA Threshold Exceeded
At 5.5 pCi/L, this reading is above the EPA action level. Prompt mitigation planning is recommended after confirmatory testing.
Typical mitigation systems reduce radon by 80-99%. See your itemized cost estimate below.
Understanding Radon Levels: Complete Reference
Below 2.0 pCi/L - Lower Concern, Keep Testing
Below both the EPA (4.0) and WHO (2.7) action reference levels. This usually means mitigation is not the next immediate step after a confirmed result. The average outdoor radon level is approximately 0.4 pCi/L, and there is no known risk-free indoor level. Periodic testing is still recommended because levels can change over time due to seasonal variations, changes in home ventilation, or foundation settling.
-4.0
2.0 - 4.0 pCi/L - Elevated, Consider Action
Exceeds the World Health Organization's reference level of 2.7 pCi/L but falls below the US EPA action threshold. The EPA states that homeowners should "consider fixing" homes in this range, especially if the home has a basement used as living space, if children are present, or in connection with a real estate transaction. Practical next step: run a confirmatory long-term test, then compare mitigation quotes if levels remain elevated.
-8.0
4.0 - 8.0 pCi/L - Action Recommended
Exceeds the EPA action level of 4.0 pCi/L. The EPA and Surgeon General strongly recommend mitigation within a few months. At this level, prioritize confirmatory testing and contractor planning. Standard sub-slab depressurization systems typically reduce indoor levels by 80-99%.
Above 8.0 pCi/L - Urgent Action Required
At these levels, the EPA recommends expedited mitigation - ideally within weeks, not months. Occupants should minimize time in lower-level rooms until the system is installed. Use a certified mitigator and request priority scheduling to shorten high-exposure time. Many mitigators offer priority scheduling for homes above 8.0 pCi/L.
Why Radon is a Testing Priority in Warren County
The EPA map is only the starting layer for Warren County. The NJ DEP tier table makes this a testing-priority county; use the tier signal to prioritize a home test, not as a home reading. That source-backed signal is why the practical move is testing or retesting before treating the county as low urgency.
This still is not a diagnosis for any single home. Foundation type, lowest-level use, pressure differences, and small geological changes can move one house above or below the county pattern.
If you do not have a reading yet, start with a short-term test in the lowest lived-in level. If the result is 2.0-3.9 pCi/L, confirm it; if it is 4.0+ pCi/L, move into mitigation pricing or seller-credit planning.
Radon & Health: What the Science Says
lung cancer
from radon
4.0 pCi/L
Radon is a Class A carcinogen - the same classification as asbestos and tobacco smoke. The National Academy of Sciences estimates that radon causes approximately 21,000 lung cancer deaths annually in the United States, making it the leading environmental cause of cancer death.
Unlike smoking, radon exposure is involuntary and often invisible. There is no safe level of radon - risk increases linearly with exposure. The good news: radon mitigation systems are highly effective, typically reducing indoor levels by 80-99% within hours of activation.
Source: US Environmental Protection Agency, "A Citizen's Guide to Radon" (EPA 402/K-12/002). National Academy of Sciences, Biological Effects of Ionizing Radiation (BEIR VI) Report, 1999.
Step 1: Test Your Home
Testing is the only way to know your home's radon level. Zone and county data tell you the regional signal, but your home could be significantly higher or lower than the countywide pattern. Start with a valid test setup before using any cost path.
State radon programs and EPA provider guidance are the right reference before hiring or confirming local requirements.
Open the state radon programAlready Know Your Level?
If your test shows 4.0 pCi/L or higher, get an itemized cost estimate specific to Warren County - including regional labor rates and permit requirements.
Get Mitigation Cost Estimate ->NJ Radon Regulations
New Jersey requires radon testing and disclosure for all real estate transactions in Tier 1 counties under the Radon Hazard Subcode.
New Jersey requires certification for radon testers and mitigators through the NJ DEP.
How to Test for Radon in Warren County
Buy a Test Kit
Purchase a short-term charcoal test kit online or from a local hardware store. Cost: $15-$30. Place it in the lowest livable level of your home.
Wait 2-7 Days
Keep doors and windows closed (except normal entry/exit) during the test period. Avoid running whole-house fans. Mail the kit to the lab provided.
Read Your Results
If results are below 4.0 pCi/L, re-test every 2 years or use a monitor for ongoing tracking. If above 4.0, use our cost calculator to see mitigation options.
Related Radon Resources for Warren County
Explore Other NJ Counties
Official State Resource
New Jersey radon program and rules
Use the state program link to verify local radon guidance, disclosure language, and contractor credential expectations before you act on an estimate.
Disclosure rule tracked
New Jersey requires radon testing and disclosure for all real estate transactions in Tier 1 counties under the Radon Hazard Subcode.
State licensing required
New Jersey requires certification for radon testers and mitigators through the NJ DEP.
Sources & Methodology
Radon zone classifications for Warren County are sourced from the EPA's Map of Radon Zones, which uses geological surveys, indoor radon measurements, and soil permeability data to assign each county a risk tier.
Disclaimer: Zone data represents county-level screening ranges and cannot predict the radon level in any specific home. Testing is the only reliable method to determine your home's radon concentration. This content is for informational purposes and is not medical advice.
Content review: Source-level retrieval dates
Editorial and Data Transparency
- Author
- RadonVerdict Data Team (Public Data and Cost Modeling)
- Content Review
- Source-level dates shown below
- Data Retrieved At
- 2026-02-24
Primary Sources
- EPA Map of Radon Zones (retrieved 2026-02-21)
- EPA A Citizen's Guide to Radon (retrieved 2026-05-05)
- CDC Environmental Public Health Tracking - Radon Testing (retrieved 2026-05-05)
- Official NJ radon program
- US Census Bureau, 2018-2022 American Community Survey 5-Year Estimates (retrieved 2026-02-24)