Is Hennepin, OK Tap Water Safe to Drink?
Graded D, with 3 unresolved violations on record. See what was cited — and what it means for your tap. What to do next ↓
49/100
waterverge.com Hennepin, OK — Water Quality Report
Hennepin's drinking water received a grade of D (49 out of 100), indicating poor water quality. The city's 1 water system serves approximately 500 residents using purchased surface water.
Lead levels were measured at 2.0 ppb (90th percentile), well within EPA limits. This system has not yet been tested for PFAS under the EPA UCMR 5 program.
The system has 56 violations on record, including 52 health-based violations. 3 remain unresolved.
What to know about Hennepin's water
Hennepin ranks #250 out of 358 cities in Oklahoma for water quality, placing it below average in the state.
The city draws from surface water sources, which are more susceptible to seasonal runoff and agricultural contamination, requiring extensive multi-barrier treatment including coagulation, filtration, and disinfection.
As a small community water system, Hennepin may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
The system has seen 24 violations in the past five years, suggesting a pattern of compliance challenges that residents should monitor closely.
Water quality score
See methodology →Is Hennepin, OK water safe to drink?
Hennepin's drinking water has significant quality concerns based on EPA testing data. With a grade of D (49/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 1 water system serves approximately 500 residents using surface water (rivers, lakes, or reservoirs).
Recent water quality updates for Hennepin
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Hennepin's water quality assessment. Grade: D (49/100).
1 health-based. Contaminants: TTHM.
2 health-based. Contaminants: TTHM.
2 health-based. Contaminants: TTHM.
Federal disaster declaration (FEMA DR-4274). Flood event — may have impacted local water infrastructure.
Federal disaster declaration (FEMA DR-3219). Hurricane event — may have impacted local water infrastructure.
Key contaminant findings
Based on the most recent EPA sampling data for Hennepin's water supply.
Well within EPA limits.
Violation history
Hennepin's water system has 56 total violations on record, including 52 health-based violations. 3 remain unresolved. 24 violations were issued in the last 5 years.
Flood & environmental risk
Garvin County has experienced 5 federally declared disasters since 1973. Flooding and severe storms can overwhelm water treatment plants, cause sewage overflows, and introduce agricultural runoff, bacteria, and sediment into drinking water supplies. Local water sources include Wildhorse Creek Near Hoover.
Where does Hennepin's water come from?
Hennepin's drinking water comes from surface water (rivers, lakes, or reservoirs), supplied by 1 water system serving approximately 500 people. Surface water sources are more susceptible to contamination from runoff, industrial discharge, and algal blooms, requiring extensive treatment. Nearby water bodies include Wildhorse Creek Near Hoover (river).
What Hennepin residents can do
Recommended: NSF-certified water filter. This addresses the specific contaminants found in Hennepin'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.
Hennepin's area has a history of flooding. After severe weather, watch for boil water advisories from your local utility.
Data: EPA SDWIS, UCMR 5 (PFAS), FEMA, NOAA. Last updated May 2026.
Top contaminants to know
View all ↓Violation summary
Violations & advisories
Drought conditions
D1 — moderate droughtMurray County is currently in D1 (moderate 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.
Flood & disaster history
Garvin County has experienced 5 federally declared disasters since 1973. Flooding and severe weather can compromise water treatment infrastructure and introduce contaminants into drinking water supplies.
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. | 2.0 | 15 | ppb | Inorganic | Safe |
Lead level trend (90th percentile)
See how Hennepin compares by contaminant
Explore where Hennepin ranks among all Oklahoma cities for specific contaminants.
Water source & infrastructure
Where Hennepin's water comes from
Hennepin's drinking water comes primarily from surface water sources such as rivers, lakes, or reservoirs.
Surface water systems require multi-stage treatment including coagulation, sedimentation, filtration, and disinfection to meet EPA Safe Drinking Water Act standards.
These sources can be impacted by seasonal changes, stormwater runoff, upstream agriculture, and industrial discharge.
The system is operated by local government ownership and serves approximately 500 people through 1 water system.
Water bodies near Hennepin
Hennepin is located near 1 notable water body. As a surface water system, these water bodies may directly influence the city's drinking water supply.
Water systems serving Hennepin
| System Name | PWSID | Population | Source |
|---|---|---|---|
| WEST DAVIS RWD | OK3005004 | 500 | SWP |
How Hennepin compares
Full Oklahoma rankings →Hennepin's score of 49/100 is on par with the average of 45/100 among major Oklahoma cities. It outscores 9 of 10 nearby cities.
Nearby cities
View Oklahoma rankings →About Hennepin, OK
Wikipedia →Hennepin is an unincorporated community along State Highway 7 in extreme southern Garvin County, Oklahoma, United States, near the point where Carter, Garvin and Murray counties intersect. As of the 2020 census, Hennepin had a population of 143. Hennepin County was named for Father Louis Hennepin, a member of Lasalle's Louisiana Expedition.
Learn more about your water
Guides and resources related to Hennepin's water quality findings.
Explore water quality across Murray
Frequently asked questions
Is Hennepin, OK tap water safe to drink?
Hennepin's water quality earned a grade of D (49/100). Significant issues have been found. A water filter is strongly recommended. The city ranks #250 out of 358 cities tested in Oklahoma.
What contaminants are in Hennepin's water?
Lead was measured at 2.0 ppb (90th percentile). 56 violations are on record.
How is Hennepin'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 Hennepin?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Hennepin's water come from?
Hennepin's water is sourced from Purchased surface water. The city has 1 water system serving approximately 500 residents.
What health violations has Hennepin's water system had?
Hennepin has 52 health-based violations on record. The most recent violation was recorded in October 2025. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 3 violations remain unresolved.
How does Hennepin's water compare to other cities?
Hennepin ranks #250 out of 358 cities in Oklahoma (better than 30% of state cities) and #13391 out of 15744 cities nationally (15th percentile). The grade of D reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.
Does Hennepin's small water system affect quality?
Hennepin's system serves approximately 500 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 56 violations on record.