B75/100
Williston Tap Water Quality: Is It Safe to Drink? (2026 Report)
Serving 31,528 residents · North Dakota
What's In Williston's Tap Water?
69
Contaminants Tested
0
Exceed EPA Limits
0
Above EPA Goals
EPA Violation History
No violations in the past 5 years
Full EPA compliance since 2014.
Understanding violation severity
Tier 1Urgent health risk. Utility must notify all customers within 24 hours.Tier 2Important health or treatment issue. Customers notified within 30 days.Tier 3Administrative or monitoring issue. Reported in the annual water quality report.
Source: EPA Safe Drinking Water Information System (SDWIS) · Updated quarterly
Water Utility Details
WILLISTON CITY OF
Population Served
26,426
Water Source
Surface Water
System ID
ND5301012
NORTHWEST RURAL WATER DISTRICT
Population Served
5,102
Water Source
Purchased Surface Water
System ID
ND5301079
Frequently Asked Questions About Williston Water
Is Williston tap water safe to drink?
Williston, North Dakota tap water receives a grade of B (75/100), which is considered good. Out of 69 contaminants tested, none exceed EPA maximum contaminant levels (MCLs). While the water meets federal standards, some residents may still choose to use a filter for additional peace of mind.
What contaminants are in Williston's water?
69 contaminants were tested in Williston's water supply. No contaminants exceed EPA legal limits (MCLs) or health goals (MCLGs), which is a positive indicator of water quality.
Does Williston have any water quality violations?
Yes, Williston has 17 EPA violation(s) on record, with the most recent in 2023. Violation types include MR, TT, MCL. 8 of these are health-based violations, which are the most serious category.
Do I need a water filter in Williston?
Williston water meets EPA standards, so a filter is not strictly necessary. However, some residents prefer the added security of a water filter. EPA health goals (MCLGs) are stricter than legal limits and are set at levels with zero expected health risk. All contaminants are within health goals.
Where does Williston's tap water come from?
Williston's drinking water is sourced from surface water and supplied by WILLISTON CITY OF and 1 other water system(s). The system serves approximately 31,528 people. Surface water sources include rivers, lakes, and reservoirs.
How often is Williston's water tested?
Under the Safe Drinking Water Act (SDWA), water utilities are required to regularly test for over 90 contaminants. Testing frequency varies by contaminant — some are tested monthly, others quarterly or annually. Williston's water systems must report results to the EPA and publish an annual Consumer Confidence Report (CCR). The data on this page reflects the latest available EPA testing data.
How does Williston's water compare to other cities in North Dakota?
Williston's water quality score of 75/100 earns a grade of B, which is considered good. This is an above-average score compared to many cities nationwide. Visit our North Dakota state page to see how all cities in the state compare.
What should I do if I'm concerned about Williston's water quality?
If you have concerns about Williston's tap water, consider these steps: (1) Request your utility's annual Consumer Confidence Report for detailed local data. (2) Get your water independently tested through a state-certified laboratory. (3) Consider an NSF-certified water filter rated for the contaminants found in your area. (4) Contact your water utility (WILLISTON CITY OF) with specific questions. (5) Report water quality issues to your state drinking water program or the EPA Safe Drinking Water Hotline at 800-426-4791.