Is Tonkawa, OK Tap Water Safe to Drink?
Graded B- — but Copper was detected above EPA limits. Here's what's in the water and how to remove it. What to do next ↓
74.1/100
waterverge.com Tonkawa, OK — Water Quality Report
Tonkawa's drinking water received a grade of B- (74.1 out of 100), indicating fair water quality. The city's 2 water systems serve approximately 3,699 residents using groundwater.
Lead levels were measured at 1.0 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 43 violations on record, including 6 health-based violations. 15 remain unresolved.
What to know about Tonkawa's water
Tonkawa ranks #109 out of 358 cities in Oklahoma for water quality, placing it mid-range in the state.
Tonkawa 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.
The system has seen 7 violations in the past five years, suggesting a pattern of compliance challenges that residents should monitor closely.
Water quality score
See methodology →Is Tonkawa, OK water safe to drink?
Tonkawa's drinking water has significant quality concerns based on EPA testing data. With a grade of B- (74.1/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 2 water systems serve approximately 3,699 residents using groundwater (wells).
Recent water quality updates for Tonkawa
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Tonkawa's water quality assessment. Grade: B- (74.1/100).
Contaminants: E. COLI.
1 health-based. Contaminants: LEAD AND COPPER RULE REVISIONS.
Contaminants: Lead and Copper Rule.
Federal disaster declaration (FEMA DR-3411). Flood event — may have impacted local water infrastructure.
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 Tonkawa's water supply.
Well within EPA limits.
Exceeds EPA action level. Copper can leach from household plumbing — flush taps for 30 seconds before drinking.
Violation history
Tonkawa's water system has 43 total violations on record, including 6 health-based violations. 15 remain unresolved. 7 violations were issued in the last 5 years.
Flood & environmental risk
Kay County has experienced 7 federally declared disasters since 1973. Flooding and severe storms can overwhelm water treatment plants, cause sewage overflows, and introduce agricultural runoff, bacteria, and sediment into drinking water supplies. Local water sources include Salt Fork Arkansas River At Tonkawa, Chikaskia River Near Blackwell.
Where does Tonkawa's water come from?
Tonkawa's drinking water comes from groundwater (wells), supplied by 2 water systems serving approximately 3,699 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate. Nearby water bodies include Salt Fork Arkansas River At Tonkawa (river), Chikaskia River Near Blackwell (river).
What Tonkawa residents can do
Recommended: NSF-certified water filter. This addresses the specific contaminants found in Tonkawa'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.
Tonkawa's area has a history of flooding. After severe weather, watch for boil water advisories from your local utility.
Data: EPA SDWIS, UCMR 5 (PFAS), FEMA, NOAA. Last updated May 2026.
Top contaminants to know
View all ↓Violation summary
Violations & advisories
Top industrial polluters within 10 miles of Tonkawa
Industrial polluters nearby
Reported releases to surface water by facilities near Tonkawa, ranked by pounds discharged annually.
| Facility | Top chemical | To surface water (lbs/yr) | Distance |
|---|---|---|---|
CFM CORP BLACKWELL, OK74631 | — | — | 9.2 mi |
PARRISH ENTERPRISES (DBA OKLAHOMA INVESTMENT CASTING CO) BLACKWELL, OK74631 | — | — | 9.7 mi |
TONKAWA FOUNDRY INC TONKAWA, OK74653 | — | — | 0.4 mi |
A-LINE TDS INC. TONKAWA, OK74653 | — | — | 1.9 mi |
Source: EPA Toxic Release Inventory (TRI) 2023
Drought conditions
D1 — moderate droughtKay County is currently in D1 (moderate 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
Kay County has experienced 7 federally declared disasters since 1973. Flooding and severe weather can compromise water treatment infrastructure and introduce contaminants into drinking water supplies.
Recommended water filters
Based on contaminants detected in Tonkawa's water supply, we recommend the following filter types.
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. | 1.0 | 15 | ppb | Inorganic | Safe |
| Copper (90th percentile) CopperInorganic A metal that enters drinking water mainly through corrosion of copper plumbing. Small amounts are essential for health, but excess levels are harmful. Health EffectsGastrointestinal distress (nausea, vomiting, diarrhea) at short-term high levels; liver and kidney damage from long-term exposure. EPA Limit1.3 mg/L action level Common SourcesCorrosion of copper household plumbing, erosion of natural deposits. | 3.30 | 1.3 | mg/L | Inorganic | Over Limit |
Lead level trend (90th percentile)
Copper level trend (90th percentile)
See how Tonkawa compares by contaminant
Explore where Tonkawa ranks among all Oklahoma cities for specific contaminants.
Water source & infrastructure
Where Tonkawa's water comes from
Tonkawa'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 3,699 people through 2 water systems.
Water bodies near Tonkawa
Tonkawa is located near 2 notable water bodies. These water bodies contribute to the regional watershed and may indirectly affect groundwater quality.
Water systems serving Tonkawa
| System Name | PWSID | Population | Source |
|---|---|---|---|
| TONKAWA | OK2003603 | 3,299 | GW |
| Tonkawa Tribe Of Oklahoma | 062005885 | 400 | GWP |
How Tonkawa compares
Full Oklahoma rankings →Tonkawa's score of 74.1/100 is above the average of 45/100 among major Oklahoma cities. It outscores 9 of 10 nearby cities.
Nearby cities
View Oklahoma rankings →ZIP codes served by Tonkawa
The water systems serving Tonkawa cover 1 ZIP code. Select any ZIP to see which water systems serve that area.
About Tonkawa, OK
Wikipedia →Tonkawa is a city in Kay County, Oklahoma, United States, along the Salt Fork Arkansas River. The population was 3,015 as of the 2020 United States census.
Learn more about your water
Guides and resources related to Tonkawa's water quality findings.
Explore water quality across Kay
Frequently asked questions
Is Tonkawa, OK tap water safe to drink?
Tonkawa's water quality earned a grade of B- (74.1/100). Some concerns have been identified. Consider a water filter for an extra layer of protection. The city ranks #109 out of 358 cities tested in Oklahoma.
What contaminants are in Tonkawa's water?
Lead was measured at 1.0 ppb (90th percentile). 43 violations are on record.
How is Tonkawa'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 Tonkawa?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Tonkawa's water come from?
Tonkawa's water is sourced from Groundwater. The city has 2 water systems serving approximately 3,699 residents.
What health violations has Tonkawa's water system had?
Tonkawa has 6 health-based violations on record. The most recent violation was recorded in August 2025. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 15 violations remain unresolved.
Is Tonkawa's groundwater at risk of contamination?
Tonkawa 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 43 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 Tonkawa's water compare to other cities?
Tonkawa ranks #109 out of 358 cities in Oklahoma (better than 70% of state cities) and #9934 out of 15744 cities nationally (37th percentile). The grade of B- reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.