01The verdict: is Tioga water safe?
Tioga's tap water meets most EPA standards but has areas that warrant attention. With a grade of A (90.4/100), some contaminant levels or compliance issues suggest that residents may benefit from additional filtration. The city's 2 water systems serve approximately 2,202 residents using surface water (rivers, lakes, or reservoirs).
2 unresolved violations on record
EPA records show open compliance items for this system. Most are administrative, but unresolved items are worth watching.
See what was cited ↓Lead is well under the limit
90th-percentile lead is 1.7 ppb — beneath the 15 ppb federal action level and under the 5 ppb watch threshold.
See the trend ↓A flood-prone service area
8 federal disaster declarations on record. After severe weather, watch for boil-water advisories.
See the risk factors ↓Tioga's drinking water received a grade of A (90.4 out of 100), indicating excellent water quality. The city's 2 water systems serve approximately 2,202 residents using purchased surface water.
Lead levels were measured at 1.7 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 7 violations on record, including 0 health-based violations. 2 remain unresolved.
Tioga ranks #32 out of 101 cities in North Dakota for water quality, placing it mid-range 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, Tioga may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
02What's in Tioga's water
Every contaminant flagged in Tioga, on one shared scale: distance to its own legal limit. The red line is the limit — anything past it is out of compliance, and the closer a bar gets, the less headroom the system has.
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. | 1.7 | 15 | ppb | Inorganic | Safe |
Cities ranked by 90th-percentile lead PF PFAS in North Dakota
Cities ranked by compounds detected Cu Copper in North Dakota
Cities ranked by 90th-percentile copper
03Tioga's ten-year track record
Each box is one year. A green check means no EPA violations; a numbered badge counts that year's violations — red if any were health-based, amber if they were monitoring or paperwork issues. The system has 7 violations on record, including 0 health-based violations. 2 remain unresolved.
All ten of the last ten years were clean — no EPA violations recorded for Tioga.
▼ Down 2.2 ppb since 1994. Latest reading: 1.7 ppb (2024) — 11% of the action level. Sampled at higher-risk homes (90th percentile).
04Where Tioga's water comes from
Tioga's drinking water comes primarily from surface water sources such as rivers, lakes, or reservoirs.
Purchased Surface Water
Rivers, lakes, or reservoirs — more exposed to runoff, agriculture, and seasonal swings than groundwater.
Wholesale supplier
Multi-barrier treatment: coagulation, sedimentation, filtration, and disinfection to meet EPA standards.
2 systems
2 water systems, operated under local government ownership.
2,202 people
Residents served across Tioga's service area.
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 2,202 people through 2 water systems.
| System name | PWSID | Population | Source |
|---|---|---|---|
| TIOGA CITY OF | ND5300936 | 2,202 | Purchased Surface Water |
| R & T WATER SYSTEM | ND5301152 | 1,003 | Purchased Surface Water |
05Pressure on Tioga's watershed
Outside forces that shape what reaches the treatment plant. None of these is a verdict on the tap by itself — but each adds pressure worth knowing about.
Industrial discharge
3 facilities within 10 miles reported 0 lb released to surface water in the latest EPA Toxics Release Inventory. Proximity doesn't equal tap contamination — treatment and hydrology decide — but it's pressure on the watershed.
Flood & storm history
8 federal disaster declarations on record for Williams County. Flooding and severe storms can overwhelm treatment plants, cause sewage overflows, and push runoff into supplies.
Drought
Williams County is in D1 (moderate drought) per the U.S. Drought Monitor (week of Jul 2026). Drought can raise disinfection-byproduct levels and taste/odor issues as utilities draw from lower reservoirs.
06How Tioga compares
Scores for nearby North Dakota cities on one line, with the average marked.
dashed line = North Dakota average (82/100)
Tioga scores 90.4/100 — above the North Dakota average of 82/100. It outscores 6 of 10 nearby cities. Full North Dakota rankings →
91.5 / 100ABismarck, ND
85.7 / 100BMinot, ND
83.2 / 100AGrand Forks, ND
91.3 / 100ADickinson, ND
93 / 100AWest Fargo, ND
92.2 / 100
Compare all cities in the county — grades, violations, and contaminant data side by side.→
07What to do at home
Steps matched to what testing actually found in Tioga's water — not generic advice.
A basic carbon filter still helps
Tioga's water meets federal standards, but a simple carbon filter improves taste and adds a margin of safety against short-term issues.
Compare tested filters →Read your utility's annual report
Every utility must publish a yearly Consumer Confidence Report with its own testing results. It pairs well with the independent data on this page.
How to read a CCR →Watch for Tioga alerts
This area has a history of flood declarations — after severe weather, watch for boil-water advisories from the utility, and check the live alerts on this page.
All water alerts →Frequently asked questions
Is Tioga, ND tap water safe to drink?
Tioga's water quality earned a grade of A (90.4/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #32 out of 101 cities tested in North Dakota.
What contaminants are in Tioga's water?
Lead was measured at 1.7 ppb (90th percentile). 7 violations are on record.
How is Tioga'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 Tioga?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Tioga's water come from?
Tioga's water is sourced from Purchased surface water. The city has 2 water systems serving approximately 2,202 residents.
How does Tioga's water compare to other cities?
Tioga ranks #32 out of 101 cities in North Dakota (better than 68% of state cities) and #2225 out of 15382 cities nationally (86th percentile). The grade of A reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.