Is Hollis, OK Tap Water Safe to Drink?
Graded D+, with 9 unresolved violations on record. See what was cited — and what it means for your tap. What to do next ↓
52/100
waterverge.com Hollis, OK — Water Quality Report
Hollis's drinking water received a grade of D+ (52 out of 100), indicating poor water quality. The city's 3 water systems serve approximately 2,533 residents using groundwater.
Lead levels were measured at 0.9 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 207 violations on record, including 148 health-based violations. 9 remain unresolved.
What to know about Hollis's water
Hollis ranks #182 out of 358 cities in Oklahoma for water quality, placing it below average in the state.
Hollis 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.
As a small community water system, Hollis may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
The system has seen 36 violations in the past five years, suggesting a pattern of compliance challenges that residents should monitor closely.
Water quality score
See methodology →Is Hollis, OK water safe to drink?
Hollis's drinking water has significant quality concerns based on EPA testing data. With a grade of D+ (52/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 3 water systems serve approximately 2,533 residents using groundwater (wells).
Recent water quality updates for Hollis
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Hollis's water quality assessment. Grade: D+ (52/100).
1 health-based. Contaminants: Nitrate-Nitrite.
1 health-based. Contaminants: Nitrate-Nitrite.
1 health-based. Contaminants: Nitrate-Nitrite.
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 Hollis's water supply.
Well within EPA limits.
Violation history
Hollis's water system has 207 total violations on record, including 148 health-based violations. 9 remain unresolved. 36 violations were issued in the last 5 years.
Flood & environmental risk
Harmon County has experienced 1 federally declared disaster since 2005. Flooding and severe storms can overwhelm water treatment plants, cause sewage overflows, and introduce agricultural runoff, bacteria, and sediment into drinking water supplies.
Where does Hollis's water come from?
Hollis's drinking water comes from groundwater (wells), supplied by 3 water systems serving approximately 2,533 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate.
What Hollis residents can do
Recommended: NSF-certified water filter. This addresses the specific contaminants found in Hollis'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.
Data: EPA SDWIS, UCMR 5 (PFAS), FEMA, NOAA. Last updated May 2026.
Top contaminants to know
View all ↓Violation summary
Violations & advisories
Drought conditions
D3 — extreme droughtGreer County is currently in D3 (extreme 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
Harmon County has experienced 1 federally declared disaster since 2005. 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. | 0.9 | 15 | ppb | Inorganic | Safe |
Lead level trend (90th percentile)
See how Hollis compares by contaminant
Explore where Hollis ranks among all Oklahoma cities for specific contaminants.
Water source & infrastructure
Where Hollis's water comes from
Hollis'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 2,533 people through 3 water systems.
Water systems serving Hollis
| System Name | PWSID | Population | Source |
|---|---|---|---|
| HOLLIS | OK2002901 | 2,264 | GW |
| HARMON ELECTRIC | OK3002801 | 188 | GWP |
| THIRSTY WATER CORP | OK2002806 | 81 | GW |
How Hollis compares
Full Oklahoma rankings →Hollis's score of 52/100 is above the average of 45/100 among major Oklahoma cities. It outscores 9 of 10 nearby cities.
Nearby cities
View Oklahoma rankings →About Hollis, OK
Learn more about your water
Guides and resources related to Hollis's water quality findings.
Explore water quality across Harmon
Frequently asked questions
Is Hollis, OK tap water safe to drink?
Hollis's water quality earned a grade of D+ (52/100). Significant issues have been found. A water filter is strongly recommended. The city ranks #182 out of 358 cities tested in Oklahoma.
What contaminants are in Hollis's water?
Lead was measured at 0.9 ppb (90th percentile). 207 violations are on record.
How is Hollis'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 Hollis?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Hollis's water come from?
Hollis's water is sourced from Groundwater. The city has 3 water systems serving approximately 2,533 residents.
What health violations has Hollis's water system had?
Hollis has 148 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. 9 violations remain unresolved.
Is Hollis's groundwater at risk of contamination?
Hollis 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 207 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 Hollis's water compare to other cities?
Hollis ranks #182 out of 358 cities in Oklahoma (better than 49% of state cities) and #12807 out of 15744 cities nationally (19th percentile). The grade of D+ reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.