Data: EPA Safe Drinking Water Information System (SDWIS) Last verified: 2026-05-03

Herndon, VA — clean EPA record, 2 water systems, zero violations.

Water Quality Map: Herndon, VA

Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.

A B C D F

Water Quality by ZIP Code in Herndon

Water quality varies across Herndon's 6 ZIP codes. Check your specific ZIP for detailed contaminant data.

ZIP Code	Grade	Score	Violations	Health
20170	C	65	0	0	View report →
20171	C	65	0	0	View report →
20172	C	66	0	0	View report →
20192	C	66	0	0	View report →
20193	C	66	0	0	View report →
22095	C	66	0	0	View report →

Water Quality Overview

Herndon, Virginia receives a water quality grade of C with an overall score of 66 out of 100, based on EPA compliance data from the Safe Drinking Water Information System (SDWIS).

No EPA violations have been recorded for the 2 water systems serving Herndon. This is a positive indicator, though it does not guarantee the absence of all contaminants — some substances (like PFAS) are not yet fully regulated.

What Grade C Means

A grade of C indicates moderate compliance issues. Herndon's water systems have some violations that warrant attention. While the water may still be safe for most people, residents in affected ZIP codes should consider additional testing or filtration.

Lead Levels

The average 90th percentile lead level across Herndon water systems is 0.0012 mg/L — within EPA limits. No ZIP codes exceed the EPA lead action level.

With 43% of homes built before 1986, Herndon has a higher-than-average risk of lead from older plumbing. Lead solder was banned in 1986, and homes built before this date may have lead in pipes, solder joints, or fixtures.

Radon Risk

Herndon is in EPA Radon Zone 1 (High risk). The EPA recommends all homes in Zone 1 areas be tested for radon. Radon is the second leading cause of lung cancer after smoking.

Water Systems Serving Herndon

Herndon is served by 2 community water systems regulated under the Safe Drinking Water Act. These systems collectively serve approximately 1,146,214 people across 6 ZIP codes.

Each water system is identified by a Public Water System ID (PWSID) and is required to:

• Test for over 90 regulated contaminants on a regular schedule
• Report results to the EPA and state regulators
• Issue an annual Consumer Confidence Report (CCR) to all customers
• Take corrective action when violations occur

How to Check Your Water in Herndon

1. Enter your ZIP code on ZipCheckup to see your specific water system data, including contaminant levels, violation history, and safety scores

2. Request your CCR — your water utility must provide an annual Consumer Confidence Report with detailed test results for all monitored contaminants

3. Get a home test — certified kits cost $20–$50 and test for lead, bacteria, and common contaminants. Professional lab tests ($150–$400) cover a broader panel

4. Consider filtration — NSF-certified filters can remove specific contaminants. Reverse osmosis removes the broadest range; activated carbon is effective for chlorine and many organics

5. Check for advisories — monitor your local utility website and local news for boil water advisories or system alerts

Herndon vs. Nearby Virginia Cities

How Herndon's water quality compares to similar cities in Virginia:

Recommended Water Filters for Herndon

Based on contaminants detected in Herndon's water supply, these filter types are recommended:

Reverse Osmosis (under-sink)

• Removes: Lead
• Effectiveness: 95-99%
• Cost range: $150–$500
• Certification: NSF/ANSI 58
• Recommended products:
  • Waterdrop G3P800
  • Aquasana AQ-5200
  • Clearly Filtered Pitcher

Water Quality by ZIP Code in Herndon

Water quality varies across Herndon's ZIP codes. The table below shows the worst-scoring and best-scoring areas:

Common Questions About Herndon Water

These are the most common questions residents search for about water quality in Herndon, Virginia:

Is Herndon water hard or soft? Water hardness varies by source. Herndon's 2 water systems use multiple sources. Check your ZIP code report for specific hardness data.

Can I drink Herndon tap water? Herndon's water receives a grade of C (66/100). No health-based violations have been recorded, but home testing is always recommended.

What is the best water filter for Herndon? Based on detected contaminants, a reverse osmosis (under-sink) filter is most recommended. See our Water Filter Matcher for personalized recommendations.

Herndon vs. Virginia Average

Understanding how Herndon compares to the broader Virginia average helps contextualize your local water quality. Factors like water source, treatment methods, and infrastructure age all contribute to differences between cities in the same state.

To see how individual neighborhoods compare, check the ZIP code reports below — water quality can vary significantly even within Herndon.

ZIP Codes in Herndon

Herndon spans 6 ZIP codes. Each ZIP code has its own water quality profile based on the specific water system serving that area. Check each ZIP code for detailed contaminant data, violation history, and system information.

Data Sources

• Water quality: EPA Safe Drinking Water Information System (SDWIS)
• Lead/copper: EPA Lead and Copper Rule sampling data
• Radon: EPA Map of Radon Zones
• Enforcement: EPA ECHO database
• Filter recommendations: NSF/ANSI certified products

Updated daily.