Is Twin Oaks, OK Tap Water Safe to Drink?
Graded C+ — but Copper was detected above EPA limits. Here's what's in the water and how to remove it. What to do next ↓
65.4/100
waterverge.com Twin Oaks, OK — Water Quality Report
Twin Oaks's drinking water received a grade of C+ (65.4 out of 100), indicating fair water quality. The city's 1 water system serves approximately 750 residents using purchased surface water.
Lead levels were measured at 0.0 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 28 violations on record, including 1 health-based violation. 20 remain unresolved.
What to know about Twin Oaks's water
Twin Oaks ranks #136 out of 358 cities in Oklahoma 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, Twin Oaks may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
The system has seen 11 violations in the past five years, suggesting a pattern of compliance challenges that residents should monitor closely.
Water quality score
See methodology →Is Twin Oaks, OK water safe to drink?
Twin Oaks's drinking water has significant quality concerns based on EPA testing data. With a grade of C+ (65.4/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 1 water system serves approximately 750 residents using surface water (rivers, lakes, or reservoirs).
Recent water quality updates for Twin Oaks
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Twin Oaks's water quality assessment. Grade: C+ (65.4/100).
Contaminants: Lead and Copper Rule.
1 health-based. Contaminants: LEAD AND COPPER RULE REVISIONS.
Contaminants: Consumer Confidence 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 Twin Oaks'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
Twin Oaks's water system has 28 total violations on record, including 1 health-based violation. 20 remain unresolved. 11 violations were issued in the last 5 years.
Flood & environmental risk
Delaware County has experienced 4 federally declared disasters since 1974. 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 Spavinaw Creek Near Colcord, Saline Creek Near Bull Hollow, Flint Creek Near Kansas, Illinois River At Chewey.
Where does Twin Oaks's water come from?
Twin Oaks's drinking water comes from surface water (rivers, lakes, or reservoirs), supplied by 1 water system serving approximately 750 people. Surface water sources are more susceptible to contamination from runoff, industrial discharge, and algal blooms, requiring extensive treatment. Nearby water bodies include Spavinaw Creek Near Colcord (river), Saline Creek Near Bull Hollow (river), Flint Creek Near Kansas (river), Illinois River At Chewey (river).
What Twin Oaks residents can do
Recommended: NSF-certified water filter. This addresses the specific contaminants found in Twin Oaks'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.
Twin Oaks'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 droughtDelaware 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
Delaware County has experienced 4 federally declared disasters since 1974. Flooding and severe weather can compromise water treatment infrastructure and introduce contaminants into drinking water supplies.
Recommended water filters
Based on contaminants detected in Twin Oaks'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. | 0.0 | 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. | 1.73 | 1.3 | mg/L | Inorganic | Over Limit |
Lead level trend (90th percentile)
Copper level (90th percentile)
Latest reading: 1.725 mg/L (2012)
EPA action level: 1.3 mg/L
See how Twin Oaks compares by contaminant
Explore where Twin Oaks ranks among all Oklahoma cities for specific contaminants.
Water source & infrastructure
Where Twin Oaks's water comes from
Twin Oaks'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 750 people through 1 water system.
Water bodies near Twin Oaks
Twin Oaks is located near 4 notable water bodies. As a surface water system, these water bodies may directly influence the city's drinking water supply.
Water systems serving Twin Oaks
| System Name | PWSID | Population | Source |
|---|---|---|---|
| DELAWARE CO RWSG&SWM DISTRICT 11 | OK3002157 | 750 | SWP |
How Twin Oaks compares
Full Oklahoma rankings →Twin Oaks's score of 65.4/100 is above the average of 45/100 among major Oklahoma cities. It outscores 9 of 10 nearby cities.
Nearby cities
View Oklahoma rankings →About Twin Oaks, OK
Wikipedia →Twin Oaks is an unincorporated community and census-designated place (CDP) in Delaware County, Oklahoma, United States. As of the 2020 census, Twin Oaks had a population of 328. A tornado hit the town on March 12, 2006, destroying 42 homes and injuring 8 people in Delaware County.
Learn more about your water
Guides and resources related to Twin Oaks's water quality findings.
Explore water quality across Delaware
Frequently asked questions
Is Twin Oaks, OK tap water safe to drink?
Twin Oaks's water quality earned a grade of C+ (65.4/100). Some concerns have been identified. Consider a water filter for an extra layer of protection. The city ranks #136 out of 358 cities tested in Oklahoma.
What contaminants are in Twin Oaks's water?
Lead was measured at 0.0 ppb (90th percentile). 28 violations are on record.
How is Twin Oaks'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 Twin Oaks?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Twin Oaks's water come from?
Twin Oaks's water is sourced from Purchased surface water. The city has 1 water system serving approximately 750 residents.
What health violations has Twin Oaks's water system had?
Twin Oaks has 1 health-based violation on record. The most recent violation was recorded in October 2025. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 20 violations remain unresolved.
How does Twin Oaks's water compare to other cities?
Twin Oaks ranks #136 out of 358 cities in Oklahoma (better than 62% of state cities) and #11518 out of 15744 cities nationally (27th percentile). The grade of C+ reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.
Does Twin Oaks's small water system affect quality?
Twin Oaks's system serves approximately 750 residents. Small community water systems (under 3,300 people) may have fewer financial resources for infrastructure upgrades and advanced treatment technologies. However, they are held to the same EPA drinking water standards as larger systems. This system has 28 violations on record.