Is Tishomingo, OK Tap Water Safe to Drink?
Graded D, with 14 unresolved violations on record. See what was cited — and what it means for your tap. What to do next ↓
47/100
waterverge.com Tishomingo, OK — Water Quality Report
Tishomingo's drinking water received a grade of D (47 out of 100), indicating poor water quality. The city's 3 water systems serve approximately 6,933 residents using surface water.
Lead levels were measured at 3.6 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 139 violations on record, including 56 health-based violations. 14 remain unresolved.
What to know about Tishomingo's water
Tishomingo ranks #275 out of 358 cities in Oklahoma for water quality, placing it among the lowest-rated 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.
The system has seen 25 violations in the past five years, suggesting a pattern of compliance challenges that residents should monitor closely.
Water quality score
See methodology →Is Tishomingo, OK water safe to drink?
Tishomingo's drinking water has significant quality concerns based on EPA testing data. With a grade of D (47/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 3 water systems serve approximately 6,933 residents using surface water (rivers, lakes, or reservoirs).
Recent water quality updates for Tishomingo
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Tishomingo's water quality assessment. Grade: D (47/100).
Contaminants: Chlorine, Revised Total Coliform Rule.
Contaminants: Consumer Confidence Rule.
Contaminants: Interim Enhanced Surface Water Treatment Rule.
Federal disaster declaration (FEMA DR-1754). 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 Tishomingo's water supply.
Well within EPA limits.
Violation history
Tishomingo's water system has 139 total violations on record, including 56 health-based violations. 14 remain unresolved. 25 violations were issued in the last 5 years.
Flood & environmental risk
Johnston County has experienced 3 federally declared disasters since 1981. 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 Washita River Near Tishomingo, Spring Creek Abv Pennington Ck Nr Mill Creek, Pennington Creek Near Reagan, Lake Texoma At Cumberland Cut Nr Cumberland, Blue River Near Connerville.
Where does Tishomingo's water come from?
Tishomingo's drinking water comes from surface water (rivers, lakes, or reservoirs), supplied by 3 water systems serving approximately 6,933 people. Surface water sources are more susceptible to contamination from runoff, industrial discharge, and algal blooms, requiring extensive treatment. Nearby water bodies include Washita River Near Tishomingo (river), Spring Creek Abv Pennington Ck Nr Mill Creek (river), Pennington Creek Near Reagan (river), Lake Texoma At Cumberland Cut Nr Cumberland (lake), Blue River Near Connerville (river).
What Tishomingo residents can do
Recommended: NSF-certified water filter. This addresses the specific contaminants found in Tishomingo'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.
Run cold water for 30 seconds before drinking, especially in the morning. Lead and copper leach from household plumbing when water sits in pipes.
Tishomingo'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
Drought conditions
D1 — moderate droughtJohnston 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
Johnston County has experienced 3 federally declared disasters since 1981. Flooding and severe weather can compromise water treatment infrastructure and introduce contaminants into drinking water supplies.
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. | 3.6 | 15 | ppb | Inorganic | Safe |
Lead level trend (90th percentile)
See how Tishomingo compares by contaminant
Explore where Tishomingo ranks among all Oklahoma cities for specific contaminants.
Water source & infrastructure
Where Tishomingo's water comes from
Tishomingo's drinking water comes primarily from surface water sources such as rivers, lakes, or reservoirs.
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 6,933 people through 3 water systems.
Water bodies near Tishomingo
Tishomingo is located near 5 notable water bodies. As a surface water system, these water bodies may directly influence the city's drinking water supply.
Water systems serving Tishomingo
| System Name | PWSID | Population | Source |
|---|---|---|---|
| TISHOMINGO MUNICIPAL AUTHORITY | OK1010815 | 3,000 | SW |
| JOHNSTON CO RWD #3 | OK2003511 | 2,783 | GW |
| MURRAY STATE COLLEGE | OK1010816 | 1,150 | SW |
How Tishomingo compares
Full Oklahoma rankings →Tishomingo's score of 47/100 is on par with the average of 45/100 among major Oklahoma cities. It outscores 8 of 10 nearby cities.
Nearby cities
View Oklahoma rankings →About Tishomingo, OK
Learn more about your water
Guides and resources related to Tishomingo's water quality findings.
Explore water quality across Johnston
Frequently asked questions
Is Tishomingo, OK tap water safe to drink?
Tishomingo's water quality earned a grade of D (47/100). Significant issues have been found. A water filter is strongly recommended. The city ranks #275 out of 358 cities tested in Oklahoma.
What contaminants are in Tishomingo's water?
Lead was measured at 3.6 ppb (90th percentile). 139 violations are on record.
How is Tishomingo'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 Tishomingo?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Tishomingo's water come from?
Tishomingo's water is sourced from Surface water. The city has 3 water systems serving approximately 6,933 residents.
What health violations has Tishomingo's water system had?
Tishomingo has 56 health-based violations on record. The most recent violation was recorded in November 2025. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 14 violations remain unresolved.
How does Tishomingo's water compare to other cities?
Tishomingo ranks #275 out of 358 cities in Oklahoma (better than 23% of state cities) and #13695 out of 15744 cities nationally (13th percentile). The grade of D reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.