Is Calera, OK Tap Water Safe to Drink?
Graded D+, with 6 unresolved violations on record. See what was cited — and what it means for your tap. What to do next ↓
50/100
waterverge.com Calera, OK — Water Quality Report
Calera's drinking water received a grade of D+ (50 out of 100), indicating poor water quality. The city's 1 water system serves approximately 2,815 residents using groundwater.
Lead levels were measured at 0.8 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 49 violations on record, including 35 health-based violations. 6 remain unresolved.
What to know about Calera's water
Calera ranks #217 out of 358 cities in Oklahoma for water quality, placing it below average in the state.
Calera 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.
As a small community water system, Calera may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
The system has seen 42 violations in the past five years, suggesting a pattern of compliance challenges that residents should monitor closely.
Water quality score
See methodology →Is Calera, OK water safe to drink?
Calera's drinking water has significant quality concerns based on EPA testing data. With a grade of D+ (50/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 1 water system serves approximately 2,815 residents using groundwater (wells).
Recent water quality updates for Calera
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Calera's water quality assessment. Grade: D+ (50/100).
1 health-based. Contaminants: LEAD AND COPPER RULE REVISIONS.
Contaminants: Revised Total Coliform Rule.
Contaminants: Revised Total Coliform Rule, Chlorine.
Federal disaster declaration (FEMA DR-3219). Hurricane event — may have impacted local water infrastructure.
Federal disaster declaration (FEMA DR-649). Flood event — may have impacted local water infrastructure.
Key contaminant findings
Based on the most recent EPA sampling data for Calera's water supply.
Well within EPA limits.
Violation history
Calera's water system has 49 total violations on record, including 35 health-based violations. 6 remain unresolved. 42 violations were issued in the last 5 years.
Flood & environmental risk
Bryan County has experienced 3 federally declared disasters since 1972. 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 Red Rv At Denison Dam Nr Denison.
Where does Calera's water come from?
Calera's drinking water comes from groundwater (wells), supplied by 1 water system serving approximately 2,815 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate. Nearby water bodies include Red Rv At Denison Dam Nr Denison (river).
What Calera residents can do
Recommended: NSF-certified water filter. This addresses the specific contaminants found in Calera'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.
Calera'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 Calera
Industrial polluters nearby
Reported releases to surface water by facilities near Calera, ranked by pounds discharged annually.
Total reported releases to surface water: 42 lbs
| Facility | Top chemical | To surface water (lbs/yr) | Distance |
|---|---|---|---|
CMC STEEL OKLAHOMA LLC DURANT, OK74701 | Zinc compounds | 42 | 5.9 mi |
ROLL-OFFS USA MEAD, OK73449 | — | — | 5.3 mi |
CARDINAL FG-DURANT DURANT, OK74701 | — | — | 4.8 mi |
DURANT BATCH PLANT DURANT, OK74701 | — | — | 6.7 mi |
DURANT READY MIX DURANT, OK74701 | — | — | 5.3 mi |
Source: EPA Toxic Release Inventory (TRI) 2023
Drought conditions
D1 — moderate droughtBryan 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
Bryan County has experienced 3 federally declared disasters since 1972. 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. | 0.8 | 15 | ppb | Inorganic | Safe |
Lead level trend (90th percentile)
See how Calera compares by contaminant
Explore where Calera ranks among all Oklahoma cities for specific contaminants.
Water source & infrastructure
Where Calera's water comes from
Calera'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 2,815 people through 1 water system.
Water bodies near Calera
Calera is located near 1 notable water body. These water bodies contribute to the regional watershed and may indirectly affect groundwater quality.
Water systems serving Calera
| System Name | PWSID | Population | Source |
|---|---|---|---|
| CALERA PWA | OK2000702 | 2,815 | GW |
How Calera compares
Full Oklahoma rankings →Calera's score of 50/100 is on par with the average of 45/100 among major Oklahoma cities. It outscores 9 of 10 nearby cities.
Nearby cities
View Oklahoma rankings →About Calera, OK
Learn more about your water
Guides and resources related to Calera's water quality findings.
Explore water quality across Bryan
Frequently asked questions
Is Calera, OK tap water safe to drink?
Calera's water quality earned a grade of D+ (50/100). Significant issues have been found. A water filter is strongly recommended. The city ranks #217 out of 358 cities tested in Oklahoma.
What contaminants are in Calera's water?
Lead was measured at 0.8 ppb (90th percentile). 49 violations are on record.
How is Calera'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 Calera?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Calera's water come from?
Calera's water is sourced from Groundwater. The city has 1 water system serving approximately 2,815 residents.
What health violations has Calera's water system had?
Calera has 35 health-based violations on record. The most recent violation was recorded in October 2024. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 6 violations remain unresolved.
Is Calera's groundwater at risk of contamination?
Calera 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 49 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 Calera's water compare to other cities?
Calera ranks #217 out of 358 cities in Oklahoma (better than 39% of state cities) and #13094 out of 15744 cities nationally (17th percentile). The grade of D+ reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.
Does Calera's small water system affect quality?
Calera's system serves approximately 2,815 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 49 violations on record.