Siasconset Water Department
PWSID: MA4197001
This system has no unresolved violations. The most recent violation on record was 2025-04-01.
This system has more violations on record than 98% of water systems in Massachusetts.
Violation trend: 15.8 per year over the last 5 years.
System Details
| Population Served | 3,000 |
| Service Connections | 852 |
| Water Source | Groundwater |
| System Type | Community Water System |
| Owner | Local Government |
| Status | Active |
| City | Nantucket |
| EPA ZIP on File | 02554 |
Areas Served
- Nantucket, Nantucket County, 02564
Lead & Copper Testing
| Contaminant | Level | EPA Action Level | Status |
|---|---|---|---|
| Copper (90th percentile) | 4.1400 mg/L | 1.300 mg/L | Exceeds Action Level |
| Copper (90th percentile) | 1.4900 mg/L | 1.300 mg/L | Exceeds Action Level |
| Copper (90th percentile) | 1.4600 mg/L | 1.300 mg/L | Exceeds Action Level |
| Copper (90th percentile) | 1.4000 mg/L | 1.300 mg/L | Exceeds Action Level |
| Copper (90th percentile) | 1.4000 mg/L | 1.300 mg/L | Exceeds Action Level |
| Lead (90th percentile) | 0.0330 mg/L | 0.015 mg/L | Exceeds Action Level |
| Lead (90th percentile) | 0.0040 mg/L | 0.015 mg/L | Below Action Level |
| Lead (90th percentile) | 0.0020 mg/L | 0.015 mg/L | Below Action Level |
| Lead (90th percentile) | 0.0020 mg/L | 0.015 mg/L | Below Action Level |
| Lead (90th percentile) | 0.0020 mg/L | 0.015 mg/L | Below Action Level |
| Lead (90th percentile) | 0.0012 mg/L | 0.015 mg/L | Below Action Level |
| Lead (90th percentile) | 0.0010 mg/L | 0.015 mg/L | Below Action Level |
| Lead (90th percentile) | 0.0010 mg/L | 0.015 mg/L | Below Action Level |
| Lead (90th percentile) | 0.0000 mg/L | 0.015 mg/L | Below Action Level |
| Lead (90th percentile) | 0.0000 mg/L | 0.015 mg/L | Below Action Level |
| Lead (90th percentile) | 0.0000 mg/L | 0.015 mg/L | Below Action Level |
| Lead (90th percentile) | 0.0000 mg/L | 0.015 mg/L | Below Action Level |
Violation History (79 total)
| Contaminant | Violation | Date | Health-Based | Status |
|---|---|---|---|---|
| 1040 | MR | 2025-04-01 | Acknowledged | |
| 2051 | MR | 2024-04-01 | Acknowledged | |
| 2051 | MR | 2024-04-01 | Acknowledged | |
| 2050 | MR | 2024-04-01 | Acknowledged | |
| 2050 | MR | 2024-04-01 | Acknowledged | |
| 2046 | MR | 2024-04-01 | Acknowledged | |
| 2046 | MR | 2024-04-01 | Acknowledged | |
| 2959 | MR | 2024-04-01 | Acknowledged | |
| 2959 | MR | 2024-04-01 | Acknowledged | |
| 2105 | MR | 2024-04-01 | Acknowledged | |
| 2105 | MR | 2024-04-01 | Acknowledged | |
| 2005 | MR | 2024-04-01 | Acknowledged | |
| 2005 | MR | 2024-04-01 | Acknowledged | |
| 2946 | MR | 2024-04-01 | Acknowledged | |
| 2946 | MR | 2024-04-01 | Acknowledged | |
| 2067 | MR | 2024-04-01 | Acknowledged | |
| 2067 | MR | 2024-04-01 | Acknowledged | |
| 2065 | MR | 2024-04-01 | Acknowledged | |
| 2065 | MR | 2024-04-01 | Acknowledged | |
| 2326 | MR | 2024-04-01 | Acknowledged | |
| 2326 | MR | 2024-04-01 | Acknowledged | |
| 2020 | MR | 2024-04-01 | Acknowledged | |
| 2020 | MR | 2024-04-01 | Acknowledged | |
| 2110 | MR | 2024-04-01 | Acknowledged | |
| 2110 | MR | 2024-04-01 | Acknowledged | |
| 2015 | MR | 2024-04-01 | Acknowledged | |
| 2015 | MR | 2024-04-01 | Acknowledged | |
| 2010 | MR | 2024-04-01 | Acknowledged | |
| 2010 | MR | 2024-04-01 | Acknowledged | |
| 2383 | MR | 2024-04-01 | Acknowledged | |
| 2383 | MR | 2024-04-01 | Acknowledged | |
| 2931 | MR | 2024-04-01 | Acknowledged | |
| 2931 | MR | 2024-04-01 | Acknowledged | |
| 2306 | MR | 2024-04-01 | Acknowledged | |
| 2306 | MR | 2024-04-01 | Acknowledged | |
| 2031 | MR | 2024-04-01 | Acknowledged | |
| 2031 | MR | 2024-04-01 | Acknowledged | |
| 2035 | MR | 2024-04-01 | Acknowledged | |
| 2035 | MR | 2024-04-01 | Acknowledged | |
| 2039 | MR | 2024-04-01 | Acknowledged | |
| 2039 | MR | 2024-04-01 | Acknowledged | |
| 2041 | MR | 2024-04-01 | Acknowledged | |
| 2041 | MR | 2024-04-01 | Acknowledged | |
| 2032 | MR | 2024-04-01 | Acknowledged | |
| 2032 | MR | 2024-04-01 | Acknowledged | |
| 2033 | MR | 2024-04-01 | Acknowledged | |
| 2033 | MR | 2024-04-01 | Acknowledged | |
| 2034 | MR | 2024-04-01 | Acknowledged | |
| 2034 | MR | 2024-04-01 | Acknowledged | |
| 2274 | MR | 2024-04-01 | Acknowledged |
Showing 50 of 79 historical violations.
Understanding This Water System's Record
Siasconset Water Department is a community water system water system that draws from groundwater sources and serves a population of 3,000 in Nantucket, Massachusetts. This page shows its complete compliance history as reported to the EPA's Safe Drinking Water Information System (SDWIS), the federal database that tracks every public water system in the United States.
What Do These Violations Mean?
Health-based violations mean the system exceeded an EPA maximum contaminant level (MCL) or failed to provide required treatment. These indicate potential health risks from contaminants like lead, arsenic, bacteria, nitrates, or disinfection byproducts. Non-health-based violations involve monitoring, reporting, or procedural requirements — the system missed a testing deadline or failed to notify customers, but contaminant levels were not necessarily unsafe.
What Should You Do?
Your water utility is required to publish an annual Consumer Confidence Report (CCR) that details test results and any violations. If your system has active health-based violations, consider a certified water filter rated for the specific contaminants involved. The contaminant guides on this site explain health risks and filter options for common pollutants. For the most current results, contact your water utility directly — EPA data can lag weeks or months behind real-time testing.