Loudoun Water - Central System
Ashburn, Virginia · PWSID: VA6107350
Ashburn Water Quality Summary
Loudoun Water - Central System supplies drinking water to about 334,808 people in Ashburn, Virginia, and draws from surface water (rivers, lakes, or reservoirs), which requires fuller treatment for runoff, sediment, and microbial risk. On the IsWaterSafe scale it earns a good Water Safety Score of 88 out of 100 (Grade B), a composite of its EPA SDWIS violation and contaminant record.
EPA SDWIS shows no health-based or monitoring violations on record for Loudoun Water - Central System, though 4 enforcement actions are logged in its history.
Across the single substance sampled, none exceeded its EPA limit. Combined Filter Effluent sits highest relative to its ceiling, detected at 0.5 NTU against an MCL of 1 NTU (sampled October 2023) — within the legal limit.
The most recent documented episode is a health-based violation involving Combined Filter Effluent, beginning October 2023 and marked resolved June 2024.
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Detected Contaminants
| Contaminant | Detected Level | MCL (Limit) | Status | Sample Date |
|---|---|---|---|---|
| Combined Filter Effluent | 0.5 NTU | 1 NTU | Within Limit | Oct 1, 2023 |
Violation History
Frequently Asked Questions
Loudoun Water - Central System has a Water Safety Score of B (88/100). The system serves 334,808 people and has 0 health violations on record. Check the contaminant table above for specific detected substances.
Loudoun Water - Central System has 0 contaminant exceedances above EPA health guidelines. See the full contaminant detection table above for all tested substances and their levels relative to legal limits and health guidelines.
The Water Safety Score (0-100, grades A through F) is based on contaminant levels relative to legal limits, health guideline exceedances, violation history, and enforcement actions. Higher scores indicate fewer concerns.
If your water system has violations, request the Consumer Confidence Report from your utility, consider getting an independent water test from a certified lab, and look into certified water filters for specific contaminants of concern. For lead, run cold water for 30 seconds before drinking.
Water quality data sourced from EPA's Safe Drinking Water Information System (SDWIS). Safety scores are calculated based on contaminant levels, violations, and enforcement history. This is not a substitute for your utility's official Consumer Confidence Report.
Source: EPA Ground Water and Drinking Water, 2026.