Public water system · DE0000663
ActiveWilmington Water Department
At a glance
Wilmington Water Department (PWSID DE0000663) is an active community water system in New Castle County, Delaware. It reports serving 107,976 people through 37,915 service connections. Its primary water source is surface water, and EPA lists it as owned by a local government. Of the 12 most recent violations in EPA's records, 4 are health-based, and the most recent began in August 2023.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
107,976
Service connections
37,915
Primary source
SW
Surface water
System type
CWS
Community water system
System record
How does Wilmington Water Department compare with other water systems in New Castle County?
By EPA's size categories, Wilmington Water Department is a very large system (more than 100,000 people). New Castle County has 76 active public water systems, and Wilmington Water Department is the 2nd-largest of them by population served. Its population served is about 15 times the county average of 7,119 people per system, and accounts for 20% of the 541,043 people reported by systems filed under the county. Across Delaware, the 494 active systems average 2,238 people each. Nationally, the average active community water system reports serving 6,703 people, so Wilmington Water Department is about 16 times that figure.
What does “community water system” mean?
A community water system serves at least 15 connections used by year-round residents, or regularly serves at least 25 year-round residents. Homes, apartments and mobile-home parks are served by these. Delaware has 219 active community water systems, 44% of the state's 494 active systems. Surface water means the system draws its water from rivers, lakes, streams or reservoirs. 4 Delaware systems (0.8%) list surface water as their primary source.
Who owns and regulates Wilmington Water Department?
EPA lists Wilmington Water Department as owned by a local government. The DE state drinking water program is its primacy agency, the regulator with primary enforcement responsibility for the system under the Safe Drinking Water Act. 12 of the 76 active systems in New Castle County (16%) are also owned by a local government.
Does Wilmington Water Department have drinking water violations?
Of the 12 most recent violations in EPA's records, 4 are health-based, and the most recent began in August 2023. The violations listed here began between December 2001 and August 2023. By type: 5 monitoring and reporting, 3 required treatment not met, 2 public notice, recordkeeping or other, 1 monitoring and 1 contaminant level above the legal limit. The contaminant or rule involved most often is Long Term 2 Enhanced Surface Water Treatment Rule (3 of them). EPA lists 12 as resolved. Resolved means at least one resolving action is on record: the system returned to compliance, the rule no longer applies, or no further action was needed.
| Began | Violation | Contaminant or rule | Health-based | Status |
|---|---|---|---|---|
| 2023-08-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2017-10-01 | Required treatment not metFailure Submit Treatment Requirement Rpt · code 33 | Long Term 2 Enhanced Surface Water Treatment Rulecode 0800 | Yes | Resolved |
| 2015-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2015-05-01 | Monitoring and reportingMonitoring, Source Water (LT2) · code 32 | Cryptosporidiumcode 3015 | No | Resolved |
| 2015-05-01 | Monitoring and reportingMonitoring, Source Water (LT2) · code 32 | Long Term 2 Enhanced Surface Water Treatment Rulecode 0800 | No | Resolved |
| 2015-04-01 | Monitoring and reportingMonitoring, Source Water (LT2) · code 32 | Long Term 2 Enhanced Surface Water Treatment Rulecode 0800 | No | Resolved |
| 2015-04-01 | Monitoring and reportingMonitoring, Source Water (LT2) · code 32 | Cryptosporidiumcode 3015 | No | Resolved |
| 2013-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2004-05-01 | Required treatment not metTreatment Technique (SWTR and GWR) · code 41 | Surface Water Treatment Rulecode 0200 | Yes | Resolved |
| 2003-10-01 | Required treatment not metTreatment Technique (SWTR and GWR) · code 41 | Surface Water Treatment Rulecode 0200 | Yes | Resolved |
| 2002-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2001-12-01 | Monitoring and reportingMonitoring, Routine Minor (TCR) · code 24 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
The 12 most recent violations in EPA's records, newest first.Labels and codes come from EPA's SDWIS reference tables. A monitoring or reporting violation means a required test or report was missed or late; it does not by itself mean a contaminant was found. "Health-based" marks violations of a legal limit or required treatment.
Wilmington Water Department: frequently asked questions
Who runs Wilmington Water Department?
Wilmington Water Department (PWSID DE0000663) is a community water system owned by a local government. It is regulated by the DE state drinking water program.
How many people does Wilmington Water Department serve?
Wilmington Water Department reports serving 107,976 people through 37,915 service connections in New Castle County, Delaware.
Where does Wilmington Water Department get its water?
EPA SDWIS lists this system's primary water source as surface water. Surface water means the system draws its water from rivers, lakes, streams or reservoirs.
Does Wilmington Water Department have any drinking water violations?
Of the 12 most recent violations in EPA's records, 4 are health-based, and the most recent began in August 2023. A monitoring or reporting violation means a required test or report was missed or late; it does not by itself mean a contaminant was found.
Is Wilmington Water Department's water safe to drink?
AquaCensus shows EPA compliance records, not current water test results, so it cannot say whether the water is safe at a given moment. Of the 12 most recent violations in EPA's records, 4 are health-based, and the most recent began in August 2023. For current results, consult the system's annual water quality report, EPA ECHO, or the DE state drinking water program.
Where can I find Wilmington Water Department's water quality report?
As a community water system, Wilmington Water Department must deliver an annual water quality report, called a Consumer Confidence Report, to its customers by July 1 each year, covering the previous calendar year. The system can provide a copy on request.
Other water systems in New Castle County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Artesian Water Company | New Castle | 231,114 | Community | Purchased surface water |
| Veolia Water Delaware, Inc. | New Castle | 100,495 | Community | Surface water |
| Newark Water Department | New Castle | 40,000 | Community | Surface water |
| Middletown Water Department | New Castle | 17,700 | Community | Purchased surface water |
| Municipal Services Commission | New Castle | 5,549 | Community | Groundwater |
| East Ncc District | New Castle | 5,538 | Community | Groundwater |
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About this data
Source: U.S. EPA Safe Drinking Water Information System (SDWIS) and SDWA violation records, via EPA ECHO, as published October 1, 2026 — AquaCensus refreshes it quarterly. See the methodology for how records are matched, cleaned and scored.
Cite as: AquaCensus, “Wilmington Water Department, PWSID DE0000663, Delaware”, https://aquacensus.com/water-systems/delaware/wilmington-water-department-de0000663 (data as of October 1, 2026).