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Federal water data

County water report

New Castle County Water Report

Drinking-water compliance, watershed health, monitoring records, and river conditions for New Castle County, Delaware.

Water grade

A

Water score

86.0

State rank

#1

of 3

Health violations

0

EPA SDWIS, 5-year lookback

Watershed impaired

54.8%

314 water bodies assessed

Monitoring sites

136

85,708 recent measurements

Live streamflow

54%

BRANDYWINE CREEK AT WILMINGTON, DE

Water at a glance

Key Water Indicators for New Castle County

EPA SDWIS

Safety Grade

A

Score: 86.0 / 100

EPA SDWIS

Active Violations

0

5-year health-based lookback

EPA ATTAINS

Watershed Health

55% impaired

314 bodies assessed

USGS NWIS

Streamflow Snapshot

54% of mean

BRANDYWINE CREEK AT WILMINGTON, DE

EPA WQP

Monitoring Sites

136

85,708 recent readings

Source: EPA SDWIS · Safe Drinking Water Information System

Drinking Water Compliance

Compliance grade

A

Based on EPA SDWIS compliance history.

Water score

Higher scores indicate cleaner recent compliance records.

86.0/100

Health violations

0

Health-based violations

Violations per 100K served

0.0

Population-normalized SDWIS rate

Data center water stress

New Castle County has 6 facilities in the DCWSI dataset.

ByCounty's DCWSI ranks this county #15 nationally by combining its water score with mapped data center density.

DCWSIThe Data Center Water Stress Index: 60% the county's water-system stress plus 40% how concentrated data centers already are, scored 0-100. Higher means data-center density and water pressure overlap more here.

82.0

0-100 index

Facility count

6

76.0 density percentile

Discharge estimate

Not reported

EPA CWA fields where available

Water vs median

+36.0

Compared with US county median

Mapped facilities

  • COMPUTER SCIENCES CORPORATION

    NEWARK

    EPA ECHO

  • JP MORGAN CHASE - 4001 GOVERNOR PRINTZ BLVD

    WILMINGTON

    EPA ECHO

  • JP MORGAN CHASE - BEAR CHRISTIANA ROAD

    BEAR

    EPA ECHO

  • JP MORGAN CHASE - MORGAN CHRISTIANA CENT

    NEWARK

    EPA ECHO

  • LNH INC DBA HOSTING.COM - 350 PENCADER

    NEWARK

    EPA ECHO

  • LNH INC DBA HOSTING.COM - 650 PENCADER

    NEWARK

    EPA ECHO
See the New Castle County data-center reportReview methodology

Data Center Water Budget Calculator

Estimate daily water use for a hypothetical facility in New Castle County.

1 MW1,000 MW
40%100%
799K gallons/dayLow Impact

Your facility would use 0.3% of this county's existing industrial water baseline — well within sustainable range.

0.3% of county industrial baseline297.25 Mgal/day remaining headroom

Based on USGS 2020 water-use data and EPA-standard cooling intensity constants. Not a substitute for site-specific water rights analysis.

Editorial analysis

Understanding New Castle County’s Water

Drinking Water Quality Overview

EPA SDWIS

New Castle County earns an A grade for drinking water quality, scoring 86.0 out of 100. EPA's Safe Drinking Water Information System (SDWIS) records zero health-based violations over the past five years — a strong compliance signal for a heavily urbanized county.

Watershed Conditions

EPA ATTAINS

Under the Clean Water Act §303(d), EPA ATTAINS tracks whether waterways meet quality standards for drinking, recreation, and aquatic life (reporting cycle: 2022). A substantial 54.8% of assessed waterways are impaired (172 of 314 water bodies) across New Castle County's watersheds. The leading impairment causes are habitat assessment and nutrients. Impairment does not mean tap water is unsafe — it measures ambient waterway conditions upstream of treatment, not finished drinking water.

River & Streamflow Status

USGS NWIS

USGS NWIS gauge data (as of 2026-05-14T14:30:00.000-04:00) puts BRANDYWINE CREEK at 276.0 cfs — well below its long-term average at 54% of mean — low-flow conditions worth noting for water-dependent ecosystems. Streamflow is a leading indicator of drought stress, sediment load, and dilution capacity: low flows concentrate pollutants and warm water temperatures, stressing aquatic life and, in surface-water-dependent systems, the source water quality for treatment plants.

Monitoring Network

EPA WQP

EPA's Water Quality Portal (WQP) aggregates monitoring data from federal, state, and tribal agencies. New Castle County has extensive coverage with 136 active monitoring sites with 85,708 recent measurements on record. Predominant monitoring categories include physical and nutrient. More monitoring sites generally indicate greater scientific attention to local water conditions — and provide the baseline data that regulators use to set future impairment listings.

Editorial advisory

What the data suggests for New Castle County

Water Verdict

New Castle County receives an excellent water quality assessment with a grade of A and a score of 86.0 out of 100. The water supply meets or exceeds federal safety standards, and residents can generally drink tap water with confidence.

Violation Context

New Castle County has recorded zero health-based violations, indicating no recent health-based violations in the reporting period. The violation rate is zero per 100,000 people served, which is the best possible outcome.

Consumer Guidance

The EPA compliance record for New Castle County shows no recent health-based violations. No health-based violations have been recorded, placing New Castle County in the top tier for drinking-water safety. New Castle County's drinking-water compliance score is 86.0 out of 100. As a routine precaution, requesting your utility's annual Consumer Confidence Report each July gives you a full list of detected contaminants and their treatment levels. With 136 active water-quality monitoring sites in New Castle County, data coverage is strong. A pipeline streamflow snapshot from the BRANDYWINE CREEK gauge is also available on this page.

Regional Context

New Castle County has better water quality than the average county in Delaware. Its water score is 19.9 points higher than the state average, indicating stronger water system performance relative to neighboring counties.

Advisory text summarizes county-level public records and is not a replacement for your utility's current Consumer Confidence Report or direct local notices.

Contaminants & Resources

Key issues flagged in New Castle County's water environment

Watershed Impairment Causes (EPA ATTAINS)

  • 1

    Habitat Assessment

    Impairment cause per EPA Clean Water Act §303(d) assessment

  • 2

    Nutrient pollution

    Impairment cause per EPA Clean Water Act §303(d) assessment

  • 3

    Enterococcus bacteria

    Impairment cause per EPA Clean Water Act §303(d) assessment

Source: EPA ATTAINS · Reporting cycle 2022

Official EPA Resources for New Castle County

EPA How's My Waterway

Interactive watershed health data for New Castle County

EPA ECHO: Drinking Water Systems

Search water utilities and violation records for New Castle County

Consumer Confidence Reports (DE)

Annual water quality reports from utilities in Delaware

Clean Water Act §303(d)

Watershed Health

Impaired Water Bodies

54.8%

172 of 314 assessed

Moderate concern

Top Impairment Causes

  • 1

    HABITAT ASSESSMENT

  • 2

    NUTRIENTS

  • 3

    ENTEROCOCCUS

Source: EPA ATTAINS · Reporting cycle 2022

Impairment is determined under the Clean Water Act §303(d): a water body is impaired when it fails to meet state-defined quality standards for designated uses (drinking, recreation, aquatic life). Assessment coverage varies by state; counties without assessed water bodies are not shown.

Past 5 years

Water Quality Monitoring

Monitoring Sites

136

Active in the past 5 years

Measurements Recorded

86K

85,708 total readings

Most Measured

  • Physical
  • Nutrient
  • Inorganics, Major, Metals

Categories measured most frequently

Data from the EPA Water Quality Portal (WQP), aggregating monitoring records from federal, state, and tribal sources. Each measurement represents a single sample analyzed for a specific characteristic (e.g., E. coli, pH, dissolved oxygen, nitrogen).

Live USGS Streamgage

River & Stream Conditions

Current Discharge

276cfs

May 14, 6:30 PM UTC

vs Long-Term Average

54%

Well below typical

Primary Streamgage

BRANDYWINE CREEK AT WILMINGTON, DE

USGS site
01481500
Drainage area
314 sq mi
Long-term mean
509 cfs

One representative streamgage (the one with the largest drainage area in the county). Many counties have multiple gauges; this view summarizes the primary one. The long-term mean is the full-record annual average; the percent-of-typical value compares the latest reading against that average.

Free tool

Estimate Your Water Costs

Water Cost Estimate

3

3 people  ·  ~225 gal/day

Annual Total

$558

Monthly

$47

Water Bill

$558/yr

Filter Cost

$0/yr

Safety Grade for New Castle County:C — Moderate

Some violations or watershed impairment detected.

Estimates use the national average residential water rate ($0.0068/gal, EPA/AWWA 2023) and EPA WaterSense per-person consumption baseline (75 gal/person/day). Actual bills vary by utility, usage tier, and local infrastructure fees. For informational purposes only.

Try the full calculator →

New Castle County has good water quality

Learn about water restrictions and conservation in your area.

Water Restrictions →

Frequently Asked Questions

What is the water quality in New Castle County, Delaware?
New Castle County, Delaware has a drinking-water quality grade of A with a score of 86.0/100, based on EPA SDWIS compliance data. The county has 0 health-based drinking water violations over the past 5 years. Watershed health, monitoring records, and streamflow snapshots are reported separately on this page.
Are there any water violations in New Castle County?
New Castle County has 0 health-based drinking water violations recorded by the EPA over the past 5 years. Health-based violations indicate instances where contaminant levels exceeded EPA Maximum Contaminant Levels (MCLs). Zero violations is an excellent record indicating consistent compliance with federal drinking water standards.
How healthy are the watersheds in New Castle County?
EPA ATTAINS assessments under Clean Water Act §303(d) indicate 54.8% of New Castle County's 314 assessed water bodies are classified as impaired (172 impaired). The top reported causes are HABITAT ASSESSMENT, NUTRIENTS, ENTEROCOCCUS. Impairment means the water body fails to meet state quality standards for at least one designated use — drinking water source, recreation, aquatic life, or fish consumption. Note: watershed impairment doesn't always translate to tap-water issues; treatment plants can remove most regulated contaminants.
How much water-quality monitoring happens in New Castle County?
EPA's Water Quality Portal records 85,708 measurements from 136 monitoring sites in New Castle County over the past five years. The most frequently measured characteristic groups are Physical, Nutrient, Inorganics, Major, Metals. Each measurement is a single sample analyzed for one characteristic (E. coli, pH, dissolved oxygen, etc.). High monitoring density means more scientific evidence behind any reported signal — it does not by itself indicate water quality.
What's happening with rivers in New Castle County right now?
New Castle County's primary USGS streamgage on the BRANDYWINE CREEK has a pipeline snapshot of 276 cubic feet per second — 54% of the long-term mean of 508.64 cfs. This is well below typical — often a signal of drought stress on source water. For the latest gauge feed, visit waterdata.usgs.gov.
How does New Castle County water compare to the Delaware average?
New Castle County's SDWIS water quality score of 86.0/100 is higher than the Delaware state average of 66.1. The average water quality grade across Delaware is C, based on data from 3 counties with available SDWIS data.
Is tap water safe to drink in New Castle County?
Based on EPA SDWIS data, New Castle County has a water quality grade of A (86.0/100). This indicates good to excellent water quality with strong SDWIS compliance. The grade speaks to the public water system, not the watershed — for watershed-level concerns, see the Watershed Health zone. For the most up-to-date information, contact your local water utility or review your Consumer Confidence Report (CCR).
Does New Castle County have clean drinking water?
New Castle County has 0 health-based drinking water violations according to EPA records. With a water quality score of 86.0/100 and grade A, the county's drinking water meets EPA standards with no recorded health violations. Note: drinking-water compliance speaks to the public water system, not necessarily to the watershed itself — check the Watershed Health zone for ATTAINS §303(d) data.
How does New Castle County rank for water quality in Delaware?
New Castle County ranks #1 out of 3 counties in Delaware by SDWIS water quality score (1 = best). With a score of 86.0/100, it falls in the top third of counties statewide. The ranking reflects EPA SDWIS compliance only — not watershed impairment, monitoring density, or streamflow, which are tracked separately on this page.

Counties with Similar Water Quality

Kent County

Delaware

C

56.8

Water score

Sussex County

Delaware

C

55.6

Water score

Data Sources

Drinking-water compliance data from the EPA Safe Drinking Water Information System (SDWIS) via the ECHO enforcement database. Scores reflect compliance history and health-based violation counts.

Watershed health and impaired-waterway data from the EPA ATTAINS Clean Water Act §303(d) assessments, state-reported and EPA-finalized.

Water-quality monitoring counts from the EPA Water Quality Portal (WQP), federated USGS, EPA, and state agency sampling records over a rolling 5-year window.

Live streamflow from the USGS National Water Information System (NWIS), continuous discharge measurements from the largest-drainage gauge in each county, compared against the full-record long-term annual mean.

Disclaimer: This data is informational only. It is not health, legal, or professional advice. For concerns about your specific water supply, contact your local water utility.

By Evan Brooks, Data EditorUpdated Reviewed by Evan Brooks, Data Editor

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