Is Grand Coteau, LA Tap Water Safe to Drink?
Graded F — but Copper was detected above EPA limits. Here's what's in the water and how to remove it. What to do next ↓
34/100
waterverge.com Grand Coteau, LA — Water Quality Report
Grand Coteau's drinking water received a grade of F (34 out of 100), indicating failing water quality. The city's 1 water system serves approximately 1,650 residents using groundwater.
Lead levels were measured at 7.0 ppb (90th percentile), which is within EPA limits but above recommended levels. This system has not yet been tested for PFAS under the EPA UCMR 5 program.
The system has 48 violations on record, including 21 health-based violations. 37 remain unresolved.
What to know about Grand Coteau's water
Grand Coteau ranks #308 out of 309 cities in Louisiana for water quality, placing it among the lowest-rated in the state.
Grand Coteau relies on groundwater, which is generally less vulnerable to surface contamination but can be affected by naturally occurring minerals like arsenic and nitrate, as well as agricultural and industrial runoff.
While lead levels are within EPA limits, they are above the recommended 5 ppb threshold that health organizations consider ideal. A point-of-use filter adds an extra layer of protection.
As a small community water system, Grand Coteau may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
The system has seen 17 violations in the past five years, suggesting a pattern of compliance challenges that residents should monitor closely.
Water quality score
See methodology →Is Grand Coteau, LA water safe to drink?
Grand Coteau's drinking water has significant quality concerns based on EPA testing data. With a grade of F (34/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 1 water system serves approximately 1,650 residents using groundwater (wells).
Recent water quality updates for Grand Coteau
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Grand Coteau's water quality assessment. Grade: F (34/100).
1 health-based. Contaminants: Groundwater Rule.
Contaminants: Lead and Copper Rule.
1 health-based. Contaminants: LEAD AND COPPER RULE REVISIONS.
Key contaminant findings
Based on the most recent EPA sampling data for Grand Coteau's water supply.
Within EPA limits but above the American Academy of Pediatrics recommended level of 1 ppb. An NSF 53-certified filter provides additional protection.
Exceeds EPA action level. Copper can leach from household plumbing — flush taps for 30 seconds before drinking.
Violation history
Grand Coteau's water system has 48 total violations on record, including 21 health-based violations. 37 remain unresolved. 17 violations were issued in the last 5 years.
Where does Grand Coteau's water come from?
Grand Coteau's drinking water comes from groundwater (wells), supplied by 1 water system serving approximately 1,650 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate. Nearby water bodies include Bayou Teche @ Port Barre, La. (river), Bayou Teche @ Arnaudville (river), Bayou Fusilier Abv Weir At Arnaudville, La (river), Vermilion River (B. Vermilion) Near Carencro (river), Vermillion Rvr N. Of I-10 At Lafayette, La (river).
What Grand Coteau residents can do
Recommended: NSF-certified water filter. This addresses the specific contaminants found in Grand Coteau's water.
Your water utility is required to publish an annual Consumer Confidence Report (CCR) with detailed testing results. Ask for the latest copy or check your utility's website.
Run cold water for 30 seconds before drinking, especially in the morning. Lead and copper leach from household plumbing when water sits in pipes.
Data: EPA SDWIS, UCMR 5 (PFAS), FEMA, NOAA. Last updated May 2026.
Top contaminants to know
View all ↓Violation summary
Violations & advisories
Top industrial polluters within 10 miles of Grand Coteau
Industrial polluters nearby
Reported releases to surface water by facilities near Grand Coteau, ranked by pounds discharged annually.
| Facility | Top chemical | To surface water (lbs/yr) | Distance |
|---|---|---|---|
UNIVAR SOLUTIONS USA LLC CARENCRO, LA70520 | — | — | 6.8 mi |
Source: EPA Toxic Release Inventory (TRI) 2023
Drought conditions
D2 — severe droughtSaint Landry Parish is currently in D2 (severe drought) per the U.S. Drought Monitor (week of May 5, 2026). Drought can elevate disinfection-byproduct (TTHM/HAA5) levels and taste/odor issues as utilities draw from lower reservoirs.
Source: U.S. Drought Monitor, updated weekly by NDMC, USDA, and NOAA.
Recommended water filters
Based on contaminants detected in Grand Coteau's water supply, we recommend the following filter types.
Full contaminants report
| Contaminant | Detected Level | EPA Limit | Unit | Category | Status |
|---|---|---|---|---|---|
| Lead (90th percentile) LeadHeavy Metal A toxic heavy metal that can leach into drinking water from older pipes, solder, and fixtures. No amount of lead in water is considered safe. Health EffectsBrain and nervous system damage in children, kidney damage, high blood pressure, and reproductive problems in adults. EPA Limit15 ppb action level Common SourcesCorrosion of lead pipes, lead solder, brass faucets, and household plumbing. | 7.0 | 15 | ppb | Inorganic | Safe |
| Copper (90th percentile) CopperInorganic A metal that enters drinking water mainly through corrosion of copper plumbing. Small amounts are essential for health, but excess levels are harmful. Health EffectsGastrointestinal distress (nausea, vomiting, diarrhea) at short-term high levels; liver and kidney damage from long-term exposure. EPA Limit1.3 mg/L action level Common SourcesCorrosion of copper household plumbing, erosion of natural deposits. | 2.00 | 1.3 | mg/L | Inorganic | Over Limit |
Lead level trend (90th percentile)
Copper level trend (90th percentile)
See how Grand Coteau compares by contaminant
Explore where Grand Coteau ranks among all Louisiana cities for specific contaminants.
Water source & infrastructure
Where Grand Coteau's water comes from
Grand Coteau's drinking water is drawn from underground aquifers through wells.
Groundwater is naturally filtered through rock and soil layers, generally requiring less treatment than surface water. However, it can contain naturally occurring contaminants like arsenic, radon, and minerals.
Agricultural activity, septic systems, and industrial operations near well fields can introduce nitrates, pesticides, and volatile organic compounds.
The system is operated by local government ownership and serves approximately 1,650 people through 1 water system.
Water bodies near Grand Coteau
Grand Coteau is located near 5 notable water bodies. These water bodies contribute to the regional watershed and may indirectly affect groundwater quality.
Water systems serving Grand Coteau
| System Name | PWSID | Population | Source |
|---|---|---|---|
| TOWN OF GRAND COTEAU WATER SYSTEM | LA1097001 | 1,650 | GW |
How Grand Coteau compares
Full Louisiana rankings →Grand Coteau's score of 34/100 is below the average of 53/100 among major Louisiana cities. 10 of 10 nearby cities score higher.
Nearby cities
View Louisiana rankings →About Grand Coteau, LA
Wikipedia →Grand Coteau is a town in St. Landry Parish, Louisiana, United States. As of the 2020 census, Grand Coteau had a population of 776. Grand Coteau is on Interstate 49 south of Opelousas and is part of the Opelousas–Eunice Micropolitan Statistical Area. The town is a center for local farming.
Learn more about your water
Guides and resources related to Grand Coteau's water quality findings.
Explore water quality across St. Landry Parish
Frequently asked questions
Is Grand Coteau, LA tap water safe to drink?
Grand Coteau's water quality earned a grade of F (34/100). Significant issues have been found. A water filter is strongly recommended. The city ranks #308 out of 309 cities tested in Louisiana.
What contaminants are in Grand Coteau's water?
Lead was measured at 7.0 ppb (90th percentile). 48 violations are on record.
How is Grand Coteau's water quality grade calculated?
The grade is based on four factors: violation history (40%), lead and copper levels (25%), PFAS contamination (25%), and regulatory compliance (10%). The score is also adjusted based on how complete the available data is. See our methodology page for full details.
Do I need a water filter in Grand Coteau?
While lead levels are within EPA limits, a filter adds extra protection. Based on current data, basic filtration should suffice for additional peace of mind.
Where does Grand Coteau's water come from?
Grand Coteau's water is sourced from Groundwater. The city has 1 water system serving approximately 1,650 residents.
What health violations has Grand Coteau's water system had?
Grand Coteau has 21 health-based violations on record. The most recent violation was recorded in March 2025. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 37 violations remain unresolved.
Is Grand Coteau's groundwater at risk of contamination?
Grand Coteau uses groundwater, which can be affected by naturally occurring contaminants like arsenic, radon, and nitrate, as well as agricultural runoff and industrial activity. The system has 48 violations on record that may relate to groundwater quality. Groundwater systems are generally less susceptible to surface contamination but should be monitored for emerging contaminants like PFAS.
How does Grand Coteau's water compare to other cities?
Grand Coteau ranks #308 out of 309 cities in Louisiana (better than 0% of state cities) and #15584 out of 15744 cities nationally (1th percentile). The grade of F reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.
Does Grand Coteau's small water system affect quality?
Grand Coteau's system serves approximately 1,650 residents. Small community water systems (under 3,300 people) may have fewer financial resources for infrastructure upgrades and advanced treatment technologies. However, they are held to the same EPA drinking water standards as larger systems. This system has 48 violations on record.