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cis-1,2-Dichloroethylene

EPA SDWIS quarterly extract data for this analyte. Detection counts and health-based violation counts reflect the most recent federal release.

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EPA contaminant code: 2380

Total Violations
92,275
Systems Affected
14,401
Health-Based %
0.1%
Most Affected State
-

What this means

cis-1,2-Dichloroethylene appears in EPA SDWIS with 92,275 recorded violations across 14,401 public water systems. Of those, 0.1% are classified as health-based, meaning the reading exceeded a federally enforceable Maximum Contaminant Level or a treatment-technique requirement rather than a monitoring or reporting lapse. Health-based violations are the subset that trigger formal corrective action and public notification, so the share is a useful signal of real-world exposure risk rather than paperwork drift. State-level concentration data is not consistently reported for this contaminant, so regional interpretation should lean on the system table below rather than state aggregates. Utilities listed below are ranked by cumulative violation count, so a higher rank reflects persistence in the record rather than a single spike; readers comparing systems should consider population served alongside violation count to gauge how many households were actually exposed.

Violation Type Split

cis-1,2-Dichloroethylene violations broken down by EPA classification.

Health-based (0.1%) Monitoring/Reporting (99.9%)

Health-based violations indicate the contaminant exceeded an EPA Maximum Contaminant Level (MCL) or treatment-technique requirement; monitoring/reporting violations are procedural.

Most Affected Water Systems

System State Violations Population
Lake Forest Park Water District WA 475 3,171
Timber Creek MHP East & West OK 362 40
Satsop Business Park WA 266 544
Seven Estates TX 264 189
Eastside MHP OK 224 32
Pinnacle Water Association WV 203 85
Carmel Montessori Academy IL 181 40
Cobbs Lake Preserve PA 155 200
Congregation Ohr Menachem PA 150 30
Kelley Crest WA 147 45
Coal Mountain Water WV 146 80
Skyview Estates IL 136 56
Windmill Estates IL 124 65
Franklin Water Systems 3 TX 117 201
Tel Company 3 WA 107 75
Marble Water System WA 102 94
Tempo Lake Water Co WA 102 246
Imagination Station Academy, LLC NC 101 35
Walnut Cove, Town Of NC 97 2,210
Nottingham Manor M H Court PA 95 473
Dabob Cove Community WA 94 24
Willow Springs MHP IN 90 25
Robinwood Village PA 90 70
Roche Harbor Water System Inc WA 87 1,985
PA American Audubon PA 86 8,200
27 Maple Drive CT 85 38
Kuzmanich Water System WA 85 45
Sapphire Lakes Development NC 84 724
Quaker Creek Store NY 84 100
Lewis River Golf Course WA 84 300

Drinking Water Guides

Understanding Water Quality Data

What EPA SDWIS tracks, how violations are classified, and what MCLs mean.
PFAS in Drinking Water

What forever chemicals are, EPA testing results, and 2024 standards.
Is My Water Safe?

How to assess your local water quality and when to take precautions.

Frequently Asked Questions

What is cis-1,2-Dichloroethylene in drinking water? ▼
cis-1,2-Dichloroethylene is a contaminant tracked by the EPA under the Safe Drinking Water Act. It has caused 92,275 violations across 14,401 public water systems nationwide. 0.1% of these violations are health-based, meaning the contaminant exceeded Maximum Contaminant Levels (MCLs) or treatment technique requirements.
How many water systems have cis-1,2-Dichloroethylene violations? ▼
14,401 public water systems across the United States have at least one cis-1,2-Dichloroethylene violation recorded in the EPA SDWIS database.
Are cis-1,2-Dichloroethylene violations dangerous? ▼
0.1% of cis-1,2-Dichloroethylene violations are health-based, meaning the contaminant level exceeded safe limits set by the EPA. Health-based violations require corrective action by the water system. Not all violations indicate immediate health risk, but they signal that water quality standards were not met.
Which state has the most cis-1,2-Dichloroethylene violations? ▼
State-level breakdown data is not available for this contaminant.
Where does this contaminant data come from? ▼
All violation data comes from the EPA Safe Drinking Water Information System (SDWIS), which tracks compliance for all public water systems regulated under the Safe Drinking Water Act. SDWIS records violations including Maximum Contaminant Level (MCL) exceedances, treatment technique failures, and monitoring/reporting issues.

Data Sources

Contaminant violation data from the EPA Safe Drinking Water Information System (SDWIS). Violations are categorized as health-based (Maximum Contaminant Level exceedances, treatment technique failures) or monitoring/reporting violations.

Related

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Data sourced from EPA SDWIS and UCMR5 PFAS monitoring data. See our methodology for details. Retrieved and formatted by PlainWater Editorial

Disclaimer: This information is provided for informational purposes only and does not constitute professional advice. Data is sourced from the EPA Safe Drinking Water Information System (SDWIS). Consult a qualified professional before making decisions based on this data.

Read our methodology - how this data is sourced, computed, and verified.

Every figure on PlainWater is rendered directly from EPA SDWIS drinking-water data, no number is typed in by an editor. This page draws directly on EPA SDWIS data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.