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WaterSafeCheck

ZIP Code 20166 Water Quality Report

Sterling, VA · Loudoun County County

Safety Score
C

Water Safety Grade

Fair — Some compliance concerns

Health Violations

0

Total Violations

0

Lead Risk

Low

Contaminants

0

About Tap Water in ZIP Code 20166

Tap water in ZIP code 20166 (Sterling, VA) receives a C grade (score: 63/100) based on EPA monitoring data. While the water from LOUDOUN WATER - CENTRAL SYSTEM is treated and regulated, this area has a moderate violation history that residents should be aware of.

Water System

LOUDOUN WATER - CENTRAL SYSTEM

EPA ID: VA6107350

Water Source

Surface Water

Population Served

334,808 residents

County

Loudoun County County, Virginia

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Lead Levels in ZIP 20166

EPA action level: 15 ppb | Public health goal: 0 ppb

Lead Data Not Available

Lead testing data was not found in EPA records for ZIP code 20166. This may occur with very small systems or systems that report under a parent utility. Contact LOUDOUN WATER - CENTRAL SYSTEM directly to request lead testing results or a copy of their Consumer Confidence Report.

Lead exposure risk in 20166 is rated Low. EPA models estimate a 20% probability of lead exposure risk in this ZIP code based on housing age, infrastructure age, and water system data. This rating reflects newer infrastructure, lower housing age, and/or low detected lead levels. Standard precautions — flushing taps before use, using filtered water for infants — are still recommended.

Lead Exposure Risk Rating
Low
Lead Exposure Probability

EPA model estimate based on housing age and infrastructure

20%
Note: Lead levels above are the 90th percentile from EPA monitoring — meaning 90% of samples were at or below this level. Even "undetected" tap water lead doesn't account for lead leaching from home plumbing. If your home was built before 1986, individual tap testing is recommended.
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Violation History

Past 5 years — EPA SDWIS data

LOUDOUN WATER - CENTRAL SYSTEM has recorded zero violations in the EPA compliance database over the past 5 years — a strong indicator of consistent regulatory compliance and careful monitoring.

Total Violations (5 yr)
0
Health-Based Violations
0
Unresolved Violations
0
Boil Water Advisories
0
Compliance Risk
Unknown
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Contaminants Detected

Contaminants with health-based violations on record

No health-based contaminant violations are on record for ZIP code 20166. This means EPA monitoring has not found levels of regulated contaminants exceeding the Maximum Contaminant Levels (MCLs) set under the Safe Drinking Water Act — a positive indicator of water quality compliance.

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Water Source & Environmental Factors

Surface Water

This system draws water from lakes, rivers, or reservoirs. Surface water is treated to remove sediment, microorganisms, and chemical contaminants before reaching taps.

Water Source Type
Surface Water
EPA Radon Zone

Moderate potential

Zone 2
Energy Burden

% of household income spent on energy — indicator of older infrastructure

1.56%

EPA Radon Zone 2 — moderate radon potential. The EPA recommends testing your home regardless of zone designation.

🛡 What Should You Do? — ZIP 20166 Recommendations

  • ⚠ Use a certified NSF/ANSI 53 filter for drinking and cooking water if you have young children
  • ⚠ Never give unfiltered tap water to infants in formula — use certified bottled or filtered water
  • ⚠ Request a copy of the Consumer Confidence Report to see what was detected and when
  • ⚠ Call the EPA Safe Drinking Water Hotline: 1-800-426-4791

Frequently Asked Questions — ZIP 20166 Water Quality

Is tap water safe to drink in ZIP code 20166?+
Tap water in 20166 (Sterling, VA) is treated and regulated, but has a grade of C due to past violations. For most healthy adults, treated tap water is generally safe. Families with infants, young children, or immunocompromised individuals may want to use a certified water filter as a precaution.
What is the lead level in 20166 tap water?+
Lead level data from EPA monitoring is not available for 20166. Contact LOUDOUN WATER - CENTRAL SYSTEM directly for the most recent lead testing results.
Who provides tap water to 20166?+
Tap water in ZIP code 20166 is provided by LOUDOUN WATER - CENTRAL SYSTEM (EPA ID: VA6107350). This system serves approximately 334,808 residents. You can contact them directly for Consumer Confidence Reports, current advisories, and billing information.
What is the water source for 20166?+
ZIP code 20166 is served by surface water. Surface water systems draw from rivers, lakes, or reservoirs and must meet strict EPA treatment requirements including filtration and disinfection.
Does 20166 have any active water quality violations?+
No active violations are on record for ZIP code 20166. EPA data shows this water system is currently in compliance with Safe Drinking Water Act standards.
How do I get a copy of my water quality report for 20166?+
Your water utility — LOUDOUN WATER - CENTRAL SYSTEM — is required by law to send you an annual Consumer Confidence Report (CCR) by July 1 each year. You can also request it directly from the utility or find it online by searching "LOUDOUN WATER - CENTRAL SYSTEM Consumer Confidence Report." The EPA's ECHO database also has historical compliance data.
What water filter should I use in 20166?+
The right filter depends on what contaminants are present. For lead, look for a filter certified to NSF/ANSI Standard 53. For chlorine byproducts (like THMs), NSF/ANSI 42 filters work well. For a broad range of contaminants including PFAS, look for NSF/ANSI 58 (reverse osmosis) systems. For ZIP code 20166, with a clean compliance record, a standard carbon block filter meeting NSF/ANSI 42 is a good choice for taste and as a precaution.
Is 20166 tap water safe for babies and infants?+
Infants are especially vulnerable to lead, nitrates, and microbial contaminants in drinking water. Current EPA data for 20166 shows no available lead data — we recommend using a certified NSF/ANSI 53 lead filter as a precaution for infant formula. Always consult your pediatrician for guidance specific to your child's health.

Data Sources & Methodology

Water quality data for ZIP code 20166 is compiled from the EPA Safe Drinking Water Information System (SDWIS), EPA ECHO enforcement database, UCMR5 unregulated contaminant monitoring, and Consumer Confidence Reports filed by LOUDOUN WATER - CENTRAL SYSTEM. Safety scores are composite metrics derived from violation history, lead levels, enforcement actions, and infrastructure risk indicators. Data reflects a 5-year monitoring window. Last dataset update: 2024. View EPA source data →