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County water report

Terrebonne Parish Water Report

Drinking-water compliance, watershed health, monitoring records, and river conditions for Terrebonne Parish, Louisiana.

Water grade

A

Water score

86.0

State rank

#6

of 63

Health violations

0

EPA SDWIS, 5-year lookback

Watershed impaired

79.2%

96 water bodies assessed

Monitoring sites

44

10,248 recent measurements

Live streamflow

414%

Bayou Grand Caillou at Dulac, LA

Water at a glance

Key Water Indicators for Terrebonne Parish

EPA SDWIS

Safety Grade

A

Score: 86.0 / 100

EPA SDWIS

Active Violations

0

5-year health-based lookback

EPA ATTAINS

Watershed Health

79% impaired

96 bodies assessed

USGS NWIS

Streamflow Snapshot

414% of mean

Bayou Grand Caillou at Dulac, LA

EPA WQP

Monitoring Sites

44

10,248 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

Editorial analysis

Understanding Terrebonne Parish’s Water

Drinking Water Quality Overview

EPA SDWIS

Terrebonne Parish 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 mid-sized 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 large majority — 79.2% — of assessed waterways are impaired (76 of 96 water bodies) across Terrebonne Parish's watersheds. The leading impairment causes are enterococcus and dissolved oxygen. 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 2025-03-12T10:00:00.000-05:00) puts Bayou Grand Caillou at 275.0 cfs — running significantly above its long-term average at 414% of mean flow. 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. Terrebonne Parish has moderate coverage with 44 active monitoring sites with 10,248 recent measurements on record. Predominant monitoring categories include physical and organics, other. 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 Terrebonne Parish

Water Verdict

Terrebonne Parish 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

Terrebonne Parish 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 Terrebonne Parish shows no recent health-based violations. No health-based violations have been recorded, placing Terrebonne Parish in the top tier for drinking-water safety. Terrebonne Parish'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 44 active water-quality monitoring sites in Terrebonne Parish, data coverage is strong. A pipeline streamflow snapshot from the Bayou Grand Caillou gauge is also available on this page.

Regional Context

Terrebonne Parish has better water quality than the average county in Louisiana. Its water score is 55.9 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 Terrebonne Parish's water environment

Watershed Impairment Causes (EPA ATTAINS)

  • 1

    Enterococcus bacteria

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

  • 2

    Low dissolved oxygen

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

  • 3

    Non-Native Aquatic Plants

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

Source: EPA ATTAINS · Reporting cycle 2022

Official EPA Resources for Terrebonne Parish

EPA How's My Waterway

Interactive watershed health data for Terrebonne Parish

EPA ECHO: Drinking Water Systems

Search water utilities and violation records for Terrebonne Parish

Consumer Confidence Reports (LA)

Annual water quality reports from utilities in Louisiana

Clean Water Act §303(d)

Watershed Health

Impaired Water Bodies

79.2%

76 of 96 assessed

High concern

Top Impairment Causes

  • 1

    ENTEROCOCCUS

  • 2

    DISSOLVED OXYGEN

  • 3

    NON-NATIVE AQUATIC PLANTS

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

44

Active in the past 5 years

Measurements Recorded

10K

10,248 total readings

Most Measured

  • Physical
  • Organics, Other
  • 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).

Live USGS Streamgage

River & Stream Conditions

Current Discharge

275cfs

Mar 12, 3:00 PM UTC

vs Long-Term Average

414%

Well above typical

Primary Streamgage

Bayou Grand Caillou at Dulac, LA

USGS site
07381324
Long-term mean
66.4 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.

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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 Terrebonne Parish: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 →

Terrebonne Parish has good water quality

Learn about water restrictions and conservation in your area.

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Frequently Asked Questions

What is the water quality in Terrebonne Parish, Louisiana?
Terrebonne Parish, Louisiana 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 Terrebonne Parish?
Terrebonne Parish 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 Terrebonne Parish?
EPA ATTAINS assessments under Clean Water Act §303(d) indicate 79.2% of Terrebonne Parish's 96 assessed water bodies are classified as impaired (76 impaired). The top reported causes are ENTEROCOCCUS, DISSOLVED OXYGEN, NON-NATIVE AQUATIC PLANTS. 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 Terrebonne Parish?
EPA's Water Quality Portal records 10,248 measurements from 44 monitoring sites in Terrebonne Parish over the past five years. The most frequently measured characteristic groups are Physical, Organics, Other, 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.
What's happening with rivers in Terrebonne Parish right now?
Terrebonne Parish's primary USGS streamgage on the Bayou Grand Caillou has a pipeline snapshot of 275 cubic feet per second — 414% of the long-term mean of 66.4 cfs. This is well above typical — often a signal of recent precipitation or storm runoff. For the latest gauge feed, visit waterdata.usgs.gov.
How does Terrebonne Parish water compare to the Louisiana average?
Terrebonne Parish's SDWIS water quality score of 86.0/100 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 Terrebonne Parish?
Based on EPA SDWIS data, Terrebonne Parish 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 Terrebonne Parish have clean drinking water?
Terrebonne Parish 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 Terrebonne Parish rank for water quality in Louisiana?
Terrebonne Parish ranks #6 out of 63 counties in Louisiana 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

Assumption Parish

Louisiana

A

86.0

Water score

Lafourche Parish

Louisiana

A

86.0

Water score

St. Bernard Parish

Louisiana

A

86.0

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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