Herndon, VA: High Radon Risk - 66/100 (2026)
6 ZIP codes · 2 water systems · Updated 2026-07-19
ZipCheckup grade for Herndon: C.
A mixed picture - some signals here are worth your attention.
Herndon shows moderate tap water quality for VA - some areas carry documented EPA violations while others meet standards without issues.
Data: EPA SDWIS, FEMA NFIP, Census ACS Last verified: 2026-07-19
Water Quality in Herndon
We track water quality and home safety data for 6 ZIP codes in Herndon, Virginia (population ~94,168), covering 2 community water systems serving approximately 1,146,214 people region-wide.
No EPA violations have been recorded across any ZIP codes in Herndon - an excellent indicator of water quality.
Average Home Safety Score: C (66/100)
Water sources: Surface water.
Lead Risk
- Average lead level (90th percentile): 0.0012 mg/L
- 43% of housing built before 1986 (when lead solder was banned)
- 2% of housing built before 1950 (when lead pipes were standard)
- Median year built: 1990
- Most common estimated pipe material: Copper
- Lead exposure risk score: 27/100
- Estimated lead service line probability: 11%
With 43% of homes built before the 1986 lead solder ban, Herndon residents - especially those in older neighborhoods - should consider testing their tap water for lead. Homes built before 1950 are at the highest risk of having lead service lines.
Housing Age Distribution
32,889 total housing units across 6 ZIP codes:
| Era | Units | Share |
|---|---|---|
| Pre-1940 | 304 | 1% |
| 1940–1949 | 145 | 0% |
| 1950–1959 | 221 | 1% |
| 1960–1969 | 851 | 3% |
| 1970–1979 | 6,530 | 20% |
| 1980–1989 | 8,783 | 27% |
| 1990–1999 | 7,399 | 22% |
| 2000–2009 | 5,622 | 17% |
| 2010–2019 | 2,832 | 9% |
| 2020+ | 202 | 1% |
Flood Risk
FEMA National Flood Insurance Program data for Herndon:
- 48 flood insurance claims on record
- $79,019 total paid out
- $1,646 average claim payout
- Dominant FEMA flood zone: X (Low risk)
Radon Risk
Dominant EPA radon zone: Zone 1 (High Risk)
- Zone 1 (High): 6 ZIP codes
- Zone 2 (Moderate): 0 ZIP codes
- Zone 3 (Low): 0 ZIP codes
The EPA recommends testing homes in Zone 1 and Zone 2 areas for radon.
Neighborhoods by Safety Score
Safest Areas
| ZIP Code | Safety Score | Grade | Violations |
|---|---|---|---|
| 20172 | 66/100 | C | 0 |
| 20192 | 66/100 | C | 0 |
| 20193 | 66/100 | C | 0 |
| 22095 | 66/100 | C | 0 |
| 20170 | 65/100 | C | 0 |
| 20171 | 65/100 | C | 0 |
What Herndon Residents Can Do
Test Your Water
- Order a certified lab test - home test kits cost $20–50 and cover lead, bacteria, and common contaminants
- Request your utility's CCR (Consumer Confidence Report) - your water provider must publish this annually
- Check your ZIP code - each area in Herndon has different water systems and risk levels
Filter Your Water
- NSF-certified pitcher filter removes chlorine taste and some contaminants ($20–40)
- NSF 53-certified filter for lead - recommended for homes built before 1986
- Reverse osmosis system removes 95%+ of contaminants including lead, PFAS, and nitrates ($150–400)
Test for Radon
- Herndon is in a high-risk radon area
- Short-term radon test kits cost $10–25
- If levels exceed 4 pCi/L, EPA recommends professional mitigation
Stay Informed
- Visit your ZIP code report for detailed, address-level data
- Sign up for EPA water quality alerts
- Review the annual water quality report from your local utility
All ZIP Codes in Herndon
Frequently Asked Questions
Is the tap water safe to drink in Herndon, VA?
Herndon has an average Home Safety Score of 66/100 (grade C) across 6 ZIP codes. No EPA violations have been recorded. Safety varies by neighborhood - check your specific ZIP code report for details.
Does Herndon have lead in the water?
The average 90th-percentile lead level across Herndon is 0.0012 mg/L, below the EPA action level of 0.015 mg/L. No ZIP codes currently exceed the EPA lead action level. About 43% of housing was built before 1986, when lead solder was banned.
Is Herndon at risk for flooding?
FEMA data shows 48 flood insurance claims in Herndon ZIP codes, with an average payout of $1,646. Most areas are in moderate or low-risk flood zones.
Are there lead pipes in Herndon homes?
43% of Herndon housing was built before 1986, when lead solder was common in plumbing. 2% was built before 1950, when lead pipes were standard. The most common estimated pipe material is Copper. The estimated probability of lead service lines is 11%. We recommend testing your water if your home was built before 1986.
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- Lead/copper: EPA Lead and Copper Rule sampling data
- Housing age: U.S. Census Bureau American Community Survey
- Flood data: FEMA National Flood Insurance Program
- Lead exposure: Composite risk score based on housing age, water lead levels, and service line estimates
- Radon: EPA Map of Radon Zones
Updated daily.
Housing & Infrastructure in Herndon
Housing age data helps assess potential lead pipe and infrastructure risks. Newer housing stock generally means lower plumbing-related contamination risk.
Source: U.S. Census Bureau American Community Survey (ACS).
Housing Age Profile
Lead solder was federally prohibited in new plumbing in 1986. In Herndon, the median build year of 1990 puts a majority of homes in the lower-risk category for that specific contamination pathway - though the pre-1986 share shown above still carries real exposure potential at the individual household level.
Most homes in Herndon were built after 1986, reducing the risk of lead contamination from plumbing. Older homes should still be tested.
Source: U.S. Census Bureau ACS B25034.
Lead Exposure Risk for Children in Herndon
Why children are most at risk: The CDC states there is no safe level of lead exposure for children. Children under 6 absorb lead more readily than adults, and even low levels can cause developmental delays, learning difficulties, and behavioral problems.
Lead risk in Herndon appears low overall, but individual homes may differ. Testing is the only way to confirm your water's lead content.
Sources: EPA Lead and Copper Rule, U.S. Census Bureau ACS, CDC childhood lead poisoning prevention guidelines.
Flood & Climate Risk in Herndon
Flood zone coverage in Herndon is limited, and NFIP data confirms that pattern with a modest claim total. Limited flood frequency generally means limited risk of the water-quality disruptions that large flood events can trigger.
Herndon has a relatively low flood history with 48 FEMA claims on record. While risk is limited, severe weather events can still impact water infrastructure.
How flooding affects water quality: Flood events can introduce sewage, agricultural runoff, and industrial chemicals into water supplies. Even after floodwaters recede, contamination can persist in wells and aging infrastructure.
Source: FEMA National Flood Insurance Program (NFIP) claims data, FEMA flood zone designations.
What You Can Do in Herndon
- Test your water at home. City-level data shows averages - your tap may differ. NSF-certified test kits cost $20-40 and give results in days.
- Install a certified water filter. An NSF-certified pitcher or under-sink filter removes most common contaminants.
- Check your home's plumbing. Homes built before 1986 may have lead solder in pipes. A licensed plumber can assess your risk.
Deep Dive Reports
Detailed analysis for Herndon, VA