City of Williston
EPA ID: ND5301012 · 26,426 people served · 3 ZIP codes
The EPA enforcement database lists 2 active violations for City of Williston — a provider that delivers drinking water to approximately 26,426 people and has not yet formally resolved those findings.
Data: EPA SDWIS Last verified: 2026-04-02
Service Area Map
Coverage area for City of Williston Source: EPA SDWIS service area boundaries.
Service area boundary — Grade C
Service Area Demographics
The City of Williston serves a community with a median household income of $90,119 and an estimated 33,969 residents across its service area. Approximately 41% of housing stock was built before 1986, which increases the likelihood of lead service lines and older plumbing.
🌊 Where Does Your Water Come From?
City of Williston's water is drawn from rivers, lakes, or reservoirs. Surface water sources are more exposed to agricultural runoff, stormwater, and upstream discharges, but they typically receive more intensive treatment before reaching your tap.
About 0% of homes in Williams County, North Dakota rely on private wells rather than public water systems. Private well owners are responsible for their own water testing and treatment.
Wastewater Proximity Note: This service area ranks in the 60th percentile nationally for proximity to wastewater discharge points. Surface water sources near wastewater outfalls may face additional treatment challenges.
Infrastructure Risk
Detected Contaminants
How City of Williston compares to EPA limits
What This Means For You
Contaminant 1006 at 1 mg/L exceeds the EPA maximum of 0.006 mg/L. Cholesterol & blood sugar effects, liver damage. Consider reverse osmosis filtration.
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.
PFAS Detected in Service Area
PFAS ("forever chemicals") have been detected in water serving this system's area. 2 detections recorded.
Contaminant 1006 was detected in this water system. reverse osmosis filtration can reduce exposure.
Find a certified water filter →Comparable Water Systems
Similar-sized systems in North Dakota
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
City of Williston (EPA ID: ND5301012) is a community water system in North Dakota that serves approximately 26,426 people from surface water sources.
This system provides water to 3 ZIP codes across 1 community.
Average Home Safety Score: C (63/100)
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, 2024 | Contaminant 1006 | Monitoring | Unresolved |
| July 1, 2023 | Total Trihalomethanes (TTHM) | Monitoring | Unresolved |
Contaminants Detected
The following contaminants have been flagged in EPA records for this water system:
| Contaminant | Category | Violations | Health-Based |
|---|---|---|---|
| Contaminant 1006 | Other Violation | 1 | No |
| Total Trihalomethanes (TTHM) | Disinfection Byproducts | 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 |
|---|---|---|---|
| 58801 | 0.00148 mg/L | No | N/A |
| 58802 | 0.00148 mg/L | No | N/A |
| 58803 | 0.00148 mg/L | No | N/A |
Radon Risk in Service Area
Dominant radon zone for ZIP codes served by this system: Zone 1 (High Risk)
The EPA recommends testing homes in Zone 1 and Zone 2 areas for radon.
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 2 additional ZIPs 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 City of Williston (ND5301012) on EPA.gov.
Frequently Asked Questions
Is City of Williston water safe to drink?
City of Williston has only monitoring/reporting violations, which are procedural in nature. The system meets federal health-based standards.
How many people does City of Williston serve?
City of Williston serves approximately 26,426 people across 3 ZIP codes in North Dakota.
Where does City of Williston get its water?
The primary water source is surface water.
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 City of Williston 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: City of Williston Consumer Confidence Report.
ZipCheckup is not affiliated with this water utility. Treatment and source data are sourced from the utility's published CCR filings.
Based on the information from those elements, the NDDEQ has determined that our source water is moderately susceptible to potential contaminants.
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 City of Williston 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.
Federal UCMR5 PFAS Monitoring: Tested Clean
This water system was tested under the federal EPA Unregulated Contaminant Monitoring Rule (UCMR5). No PFAS compounds were detected.
Current MCL reflects the lowest state-enforceable limit (NYS 10 ppt for PFOA/PFOS, effective August 2020). The federal final MCL of 4 ppt for PFOA/PFOS (EPA April 2024 rule) is not enforceable until April 2029. Detections above 4 ppt but below 10 ppt are below current MCL but above the future federal limit.
Source: U.S. EPA UCMR5 (Unregulated Contaminant Monitoring Rule, 5th cycle) — per-system federal sampling, 2023–2025. EPA UCMR5 monitoring program →
The current Service Line Inventory for our system has been completed and is available for viewing at our office (1121 5th St E Williston).
Lead Service Line Replacement Tracker
This water utility's lead service line (LSL) replacement program is tracked from public Consumer Confidence Report filings. Email signup notifies subscribers when the utility files an updated replacement plan or progress milestone.
City of Williston
ZipCheckup is not affiliated with this water utility. LSL replacement-program data is sourced from public CCR filings published by the utility. Subscription notifications are based on automated parsing of subsequent CCR releases.
Learn more about Lead and Copper Rule replacement requirements →
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.
Aesthetic water quality
These measurements describe the look, taste, and feel of the water this utility delivers. They are not contaminant violations — they sit alongside federal Secondary Maximum Contaminant Levels (SMCLs) which the EPA publishes as non-enforceable guidance.
Aesthetic measurements from City of Williston Consumer Confidence Report.
Aesthetic measurements are reported by the utility from its annual sampling. EPA Secondary MCLs are advisory thresholds — values outside them indicate aesthetic concerns such as taste or appearance, not health violations. Federal contaminant testing is shown in the sections above.
How Water Systems Appear in Rankings
Water systems are evaluated by violation history, contaminant detections, and service population. Larger systems with more service connections appear in more rankings.
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
City of Williston (EPA ID: ND5301012) — request the latest Consumer Confidence Report or ask about specific contaminants.