Hollis
EPA ID: OK2002901 · 2,264 people served · 2 ZIP codes
Federal data shows 14 unresolved violations at Hollis — roughly 2,264 residents in the service area.
Data: EPA SDWIS Last verified: 2026-04-02
Compliance Trajectory
Worsening · Risk tier: High · 95% chance of violation in next 12 months
Violations went from 4 (2022) to 3 (2025). The pattern suggests growing compliance challenges.
Service Area Map
Coverage area for Hollis Source: EPA SDWIS service area boundaries.
Service area boundary — Grade C
Service Area Demographics
The Hollis serves a community with a median household income of $52,743 and an estimated 2,251 residents across its service area. Approximately 90% of housing stock was built before 1986, which increases the likelihood of lead service lines and older plumbing.
Environmental Justice Note: 100% of the population in this service area is classified as disadvantaged under EPA's EJScreen criteria. Communities with higher disadvantaged populations often face disproportionate environmental and health burdens, including aging water infrastructure and limited resources for remediation.
💧 Where Does Your Water Come From?
Hollis's water is pumped from underground aquifers. Groundwater is naturally filtered through rock and soil, but it can be vulnerable to PFAS contamination, nitrates from agriculture, and industrial chemicals that seep into the water table.
About 0% of homes in Harmon County, Oklahoma rely on private wells rather than public water systems. Private well owners are responsible for their own water testing and treatment.
Infrastructure Risk
Detected Contaminants
How Hollis compares to EPA limits
What This Means For You
Arsenic at 17 mg/L exceeds the EPA maximum of 0.01 mg/L.
Total Trihalomethanes (TTHM) at 1 mg/L exceeds the EPA maximum of 0.08 mg/L. Bladder & rectal cancer risk; reproductive concerns. Consider granular activated carbon (GAC) filtration.
Contaminant 2105 at 4 mg/L exceeds the EPA maximum of mg/L.
Consumer Confidence Report Rule at 3 mg/L exceeds the EPA maximum of mg/L.
Revised Total Coliform Rule at 3 presence exceeds the EPA maximum of presence.
Total Trihalomethanes (TTHM) was detected in this water system. granular activated carbon (GAC) filtration can reduce exposure.
Find a certified water filter →Comparable Water Systems
Similar-sized systems in Oklahoma
Estimated Remediation Costs
Average estimated costs across ZIP codes served by this system
Based on national averages for common remediation projects. Actual costs vary by property. Only issues flagged by EPA, FEMA, or state data for each ZIP code are included.
System Overview
Hollis (EPA ID: OK2002901) is a community water system in Oklahoma that serves approximately 2,264 people from groundwater sources.
This system provides water to 2 ZIP codes across 2 communities.
Average Home Safety Score: C (66/100)
Based on water quality violations, lead levels, and radon risk across all ZIP codes served by this system.
Violation History
Recent Violations
| Date | Contaminant | Type | Status |
|---|---|---|---|
| April 1, 2025 | Arsenic | Health-based | Unresolved |
| January 1, 2025 | Arsenic | Health-based | Unresolved |
| October 1, 2024 | Stage 1 DBP Rule | Monitoring | Unresolved |
| October 1, 2024 | Arsenic | Health-based | Unresolved |
| October 1, 2024 | Contaminant 2105 | Monitoring | Resolved |
| July 1, 2024 | Arsenic | Health-based | Unresolved |
| July 1, 2024 | Contaminant 2105 | Monitoring | Resolved |
| April 1, 2024 | Contaminant 2105 | Monitoring | Unresolved |
| January 1, 2024 | Arsenic | Health-based | Unresolved |
| January 1, 2024 | Contaminant 2105 | Monitoring | Unresolved |
| October 1, 2023 | Arsenic | Health-based | Unresolved |
| July 1, 2023 | Arsenic | Health-based | Unresolved |
| April 1, 2023 | Arsenic | Health-based | Unresolved |
Contaminants Detected
The following contaminants have been flagged in EPA records for this water system:
| Contaminant | Category | Violations | Health-Based |
|---|---|---|---|
| Arsenic | Inorganic | 17 | Yes |
| Contaminant 2105 | Other Violation | 4 | No |
| Consumer Confidence Report Rule | Reporting Failure | 3 | No |
| Revised Total Coliform Rule | Microbiological | 3 | No |
| Total Trihalomethanes (TTHM) | Disinfection Byproducts | 1 | No |
| Stage 1 DBP Rule | Treatment Failure | 1 | No |
Lead & Copper
EPA Lead and Copper Rule sampling data for ZIP codes served by this system:
| ZIP Code | Lead Level | Exceeds Limit | Sample Date |
|---|---|---|---|
| 73550 | 0.0026 mg/L | No | N/A |
Radon Risk in Service Area
Dominant radon zone for ZIP codes served by this system: Zone 3 (Low Risk)
Need help with your water quality?
Typical cost: Water test: typically $20–$50 (DIY kit) · Professional inspection: $150–$400
Find the Right Water FilterFree tip: Let cold water run for 2 minutes before drinking — this helps flush lead from your pipes.
ZIP Codes Served
Coverage: 1 ZIP code confirmed via EPA Community Water System Service Area Boundaries v3 plus 1 additional ZIP inferred from SDWIS registry data. The EPA-confirmed set is the most reliable; SDWIS-inferred entries may be narrower than the real deployment area.
Data Sources
This report uses public data from the EPA Safe Drinking Water Information System (SDWIS). View the full compliance record for Hollis (OK2002901) on EPA.gov.
Frequently Asked Questions
Is Hollis water safe to drink?
Hollis has recorded 17 health-based violations in the past 5 years. While the system is required to treat water to meet federal standards, you may want to consider additional precautions such as a certified water filter.
How many people does Hollis serve?
Hollis serves approximately 2,264 people across 2 ZIP codes in Oklahoma.
Where does Hollis get its water?
The primary water source is groundwater.
Contact Your Water Utility
Public-record contact information for the water utility serving this system. Use these channels to request water quality reports, ask about service, or report issues directly.
Contact information from HOLLIS Consumer Confidence Report.
ZipCheckup is not affiliated with this water utility, does not act as its agent, and does not provide customer support for it. Contact details shown are public-record information from CCR filings. For service issues, contact the utility directly using the information above.
Water Source & Treatment
Where this water originates and how it's treated before reaching your tap.
Source: HOLLIS Consumer Confidence Report.
ZipCheckup is not affiliated with this water utility. Treatment and source data are sourced from the utility's published CCR filings.
Treatment regime
How this utility classifies its treatment process and what each reported treatment chemical does.
Treatment chemicals and what each one does
Chemical names are reported verbatim by the utility. Purpose categories are ZipCheckup annotations based on standard drinking-water treatment practice.
Treatment classification and chemical list sourced from HOLLIS Consumer Confidence Report.
Treatment intensity is a ZipCheckup-derived classification based on the chemicals and processes the utility reports. Chemicals and contamination sources are taken verbatim from the utility's CCR filing. Routine federal monitoring and contaminant testing shown elsewhere on this page determine whether the water meets safety standards, not the treatment classification.
Lead Service Line Inventory
Service line breakdown reported under the federal Lead and Copper Rule Improvements (LCRI) inventory requirement:
Federal LCRI rule (effective October 2024) requires every public water system to inventory its service lines and complete lead-line replacement within 10 years.
Source: EPA SDWIS Federal Service Line Inventory (Phase 2) · Submitted 2026
ZipCheckup is not affiliated with the utility or state agency. Inventory figures render verbatim from the public LCRI submission cited above; ZipCheckup does not perform inspections or replacements.
Notable events and violations
This section summarizes events the utility chose to disclose in its most recent Consumer Confidence Report, plus any federal compliance violations the utility recorded against itself. Both lists are utility-authored — ZipCheckup does not audit, judge, or reorder them.
Federal compliance violations on record
These entries are taken verbatim from the utility's CCR violations section. EPA defines four broad violation categories: Maximum Contaminant Level (MCL), Treatment Technique (TT), Monitoring & Reporting (M&R), and Public Notification (PN).
-
monitoriing · Lead & Copper Rule2022-01-01 to 2024-12-31
M/R (LCR) — samples missing
-
MCL · Nitrate-Nitrite2024-07-01 to 2024-09-30
Single sample MCL exceedance
Violations record from HOLLIS Consumer Confidence Report.
Notable events from the utility's CCR
These bullet entries are the utility's own narration of operational, regulatory, or infrastructure events during the reporting period.
- Lead & Copper monitoring samples missing for 2024
ZipCheckup note: items above reflect what the utility published in its most recent CCR. Federal violation records are also tracked separately by the EPA Safe Drinking Water Information System (SDWIS) — the SDWIS record is the authoritative federal source for any specific regulatory action.
Frequently Asked Questions
What You Can Do
Test your water
Home test kits can detect lead, bacteria, and other contaminants at your tap. Find the right filter →
Check your specific ZIP code
Water quality can vary within a system. View nearest ZIP report →
Contact your utility
Hollis (EPA ID: OK2002901) — request the latest Consumer Confidence Report or ask about specific contaminants.