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EPA SDWIS

Jefferson Parish Water Quality

Jefferson Parish, Louisiana

Water Grade

B

Water Score

69.0

Violations

6

State Rank

#8

of 63 (1 = best)

EPA SDWIS Compliance

Drinking Water Quality

Water Quality Grade

B

Based on EPA compliance history and violation data

Water Score

69/100

Higher = better quality

Health Violations

6

Health-based violations

Violation Rate

1.4%

Systems with violations

Water Advisory: Jefferson Parish

Water Verdict

Jefferson Parish receives a fair water quality assessment with a grade of B and a score of 69.0 out of 100. The water supply meets baseline federal standards, but there may be periods of elevated contaminant levels or infrastructure concerns worth monitoring.

Violation Context

Jefferson Parish has recorded 6 health-based violations, indicating multiple instances where federal contaminant limits or treatment requirements were not met. At 1.4 violations per 1,000 residents, this rate is relatively low compared to many U.S. counties.

Consumer Guidance

Tap water in Jefferson Parish is generally safe to drink based on available data. Residents should still review their utility's annual Consumer Confidence Report for transparency on detected contaminants. With 6 recorded health violations, staying informed about utility communications and boil-water notices is especially important. For long-term peace of mind, request your utility's latest Consumer Confidence Report and consider independent water testing if you have specific health concerns.

Regional Context

Jefferson Parish has better water quality than the average county in Louisiana. Its water score is 38.9 points higher than the state average, indicating stronger water system performance relative to neighboring counties.

Clean Water Act §303(d)

Watershed Health

Impaired Water Bodies

81.7%

58 of 71 assessed

High concern

Top Impairment Causes

  • 1

    ENTEROCOCCUS

  • 2

    DISSOLVED OXYGEN

  • 3

    FECAL COLIFORM

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

67

Active in the past 5 years

Measurements Recorded

22K

21,784 total readings

Most Measured

  • Physical
  • Microbiological
  • Nutrient

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).

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Frequently Asked Questions

What is the water quality in Jefferson Parish, Louisiana?
Jefferson Parish, Louisiana has a drinking-water quality grade of B with a score of 69.0/100, based on EPA SDWIS compliance data. The county has 6 health-based drinking water violations over the past 5 years. Watershed health, monitoring records, and live streamflow are reported separately on this page.
Are there any water violations in Jefferson Parish?
Jefferson Parish has 6 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). Violations may have been resolved — check with your local water utility for current status.
How healthy are the watersheds in Jefferson Parish?
EPA ATTAINS assessments under Clean Water Act §303(d) indicate 81.7% of Jefferson Parish's 71 assessed water bodies are classified as impaired (58 impaired). The top reported causes are ENTEROCOCCUS, DISSOLVED OXYGEN, FECAL COLIFORM. 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 Jefferson Parish?
EPA's Water Quality Portal records 21,784 measurements from 67 monitoring sites in Jefferson Parish over the past five years. The most frequently measured characteristic groups are Physical, Microbiological, Nutrient. 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.
How does Jefferson Parish water compare to the Louisiana average?
Jefferson Parish's SDWIS water quality score of 69.0/100 is higher than the Louisiana state average of 30.1. The average water quality grade across Louisiana is F, based on data from 63 counties with available SDWIS data.
Is tap water safe to drink in Jefferson Parish?
Based on EPA SDWIS data, Jefferson Parish has a water quality grade of B (69.0/100). 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).
Why does Jefferson Parish have so many water violations?
Jefferson Parish has 6 health-based drinking water violations on record from the EPA SDWIS database. A higher violation count can result from aging infrastructure, underfunded water utilities, agricultural runoff contamination, or industrial pollution. Counties with more water systems may also see more violations simply due to scale. Residents concerned about water quality should consider independent water testing and home filtration systems.
How does Jefferson Parish rank for water quality in Louisiana?
Jefferson Parish ranks #8 out of 63 counties in Louisiana by SDWIS water quality score (1 = best). With a score of 69.0/100, 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

East Baton Rouge Parish

Louisiana

A

70.4

Water score

Orleans Parish

Louisiana

B

65.8

Water score

West Baton Rouge Parish

Louisiana

B

65.3

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, 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.

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 Logan Johnson, Founder & Data EditorUpdated Reviewed by Logan Johnson, Founder & Data Editor

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