Water Quality Data for January 1 - December 31, 2025
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EPA has established National Primary Drinking Water Regulations (NPDWRs) that set mandatory water quality standards for drinking water contaminants. These are enforceable standards called “maximum contaminant levels” (MCLs) which are established to protect the public against consumption of drinking water contaminants that present a risk to human health.
Regulated Contaminants — As required by the Oklahoma Department of Environmental Quality, the City of Tulsa tests for a total of 35 different regulated contaminants on a yearly basis — this includes more than 47,000 water quality tests performed in 2025. The City of Tulsa is required to report any detectable regulated contaminant, even if levels found were well below the maximum contaminant level. The attached table lists all regulated contaminants that were detected during water quality monitoring in 2025.
Secondary Contaminants — In addition, EPA has established National Secondary Drinking Water Regulations (NSDWRs) that set non-mandatory water quality standards as guidelines for aesthetic considerations such as taste, color, and odor.
Unregulated Contaminants — The City of Tulsa participates in Unregulated Contaminant Monitoring every five years. This monitoring helps advance the science of safe drinking water by testing water for contaminants that are not regulated by National Primary Drinking Water Regulations but are known or anticipated to occur at public water systems. This monitoring assists EPA in determining which contaminants may warrant monitoring under the Safe Drinking Water Act.
Some of the terms and abbreviations contained in this report are unique to the water industry and might not be familiar to all customers. Terms used in the table are explained below.
Maximum Contaminant Level (MCL): Highest level of a contaminant allowed in drinking water. MCLs are set as close to the Maximum Contaminant Level Goal as feasible using the best available treatment technology.
Maximum Contaminant Level Goal (MCLG): The level of a contaminant in drinking water below which there is no known or expected risk to health. MCLGs allow for a margin of safety.
Action Level (AL): Concentration of a contaminant, that if exceeded, triggers treatment or other requirements that a water system must follow. Treatment Technique (TT): A required process intended to reduce the level of a contaminant in drinking water.
Maximum Residual Disinfectant Level (MRDL): Highest level of a disinfectant allowed in drinking water. There is convincing evidence the addition of disinfectant is necessary for control of microbial contaminants.
Maximum Residual Disinfectant Level Goal (MRDLG): Level of a drinking water disinfectant below which there is no known or expected health risk. MRDLGs do not reflect benefit of the use of disinfectants to control microbial contaminants.
Locational Running Annual Average (LRAA): The average concentration calculated at each monitoring location over a 12-month period.
Running Annual Average (RAA): The average concentration calculated over a 12-month period.
Parts Per Million (ppm): Equivalent to milligrams per liter. One ppm is comparable to one drop of water in 13 gallons.
Parts per Billion (ppb): Equivalent to micrograms per liter. One ppb is comparable to one drop of water in 13,000 gallons.
Turbidity: A measure of suspended material in water. In the water field, a turbidity measurement is used to indicate the clarity of water.
Nephelometric Turbidity Unit (NTU): A unit of turbidity measurement.
Standard Unit (su): A measurement of pH.
CFU: Colony Forming Units.
pCi/L: Picocuries per liter (a measure of radioactivity).
Millirem (mrem): The unit of radiation dose.
Herbicide: Any chemical(s) used to control undesirable vegetation.
Pesticide: Generally, any substance or mixture of substances intended for preventing, destroying, repelling, or mitigating any pest.
Contaminant: Any physical, chemical, biological, or radiological substance or matter in water.
| Regulated Contaminants | Unit | Ideal Goal (MCLG*) | Highest Level Allowed (MCL*) | Our Tap Water | Compliance | Likely Source of Contaminants |
| Inorganic Compounds | ||||||
| Atrazine | ppb* | 3 | 3 | Highest Running Annual Average: 0.378***** | Yes | Runoff from herbicide used on row crops. |
| Range detected: 0 - 0.335***** | ||||||
| Barium | ppm* | 2 | 2 | Highest level: 0.057 | Yes | Naturally present in the environment, drilling waste, metal refineries. |
| Range detected: 0.036 - 0.057 | ||||||
| Chlorite | ppm | 0.8 | 1 | Highest level: 0.251 | Yes | By-product of drinking water disinfection. |
| Range detected: 0.066 - 0.251 | ||||||
| Copper | ppm | 1.3 | 1.3 (AL*) | 90th percentile = 0.304, 0 sites above AL | Yes | Corrosion of household plumbing systems, erosion of natural deposits, leaching from wood preservatives. |
| Range detected: 0 - 0.377 | ||||||
| Fluoride | ppm | 4 | 4 | Average detected: 0.68 ** | Yes | Erosion of natural deposits, water additive which promotes strong teeth, discharge from fertilizer and aluminum factories. |
| Range detected: 0.32- 0.90 | ||||||
| Lead | ppb | 0 | 15 (AL) | 90th percentile = 1.20, 0 site above AL | Yes | Corrosion of household plumbing systems, erosion of natural deposits. |
| Range detected: 0 - 3.98 | ||||||
| Nitrate/Nitrite Total | ppm | 10 / 1 | Nitrate=10 Nitrite=1 | Highest level: 0.31 | Yes | Naturally occurring, fertilizers, sewage treatment plants, leaching from septic tanks, erosion of natural deposits. |
| Range detected: 0 - 0.31 | ||||||
| Disinfection Residual | ||||||
| Chloramine as Chlorine | ppm | 4 | 4.0 (MRDL*) | Highest Running Annual Average: 2.5 | Yes | Water additive used to control microbes. |
| Range detected: 1.6 - 3.2 | ||||||
| Disinfection By-Procucts | ||||||
| Total Trihalomethanes | ppb | N/A | 80 (LRAA*) | Highest Locational Running Annal Average: 39 | Yes | By-product of drinking water disinfection. |
| Range detected: 13-56 | ||||||
| Haloacetic Acids | ppb | N/A | 60 (LRAA) | Highest Locational Running Annual Average: 24 | Yes | By-product of drinking water disinfection. |
| Range detected: 5.1 - 36 | ||||||
| Precursor Removal | ||||||
| Total Organic Carbon | N/A | N/A | TT* = Ratio must be greater than or equal to 1.00 for compliance*** (RAA*) | Running Annual Average 1.06 | Yes | Naturally found in the environment. |
| Lowest Month for Removal: March 0.89 | ||||||
| Microbiological | ||||||
| Coliform Bacteria | CFU* | 0 | Presence of Coliform bacteria in < 5% of samples | Month having the highest % positive: October | Yes | Naturally present in the environment. |
| 1 positive Coliform result in 183 samples: 0.55 % | ||||||
| Clarity | ||||||
| Turbidity | NTU* | N/A | TT*= less than 0.3 NTU 95 percent of the time. | Lowest monthly % of samples with < 0.3 NTU: 100% | Yes | Soil runoff. |
| Highest single reading: 0.14 | ||||||
| Radiological (Completed in 2024) | ||||||
| Gross Alpha | pCi/L* | 0 | 15 | < 3.00 | Yes | Erosion of natural deposits. |
| Gross Beta | pCi/L | 0 | 50 *** | <4.00 | Yes | Decay of natural and man-made deposits. |
| Radium 226 | pCi/L | 0 | 5 (Combined Total) | < 1.00 | Yes | Erosion of natural deposits. |
Radium 228 |
pCi/L | 0 | < 1.00 | Yes | Erosion of natural deposits. | |
| Uranium Total | ppb | 0 | 30 | < 1.00 | Yes | Erosion of natural deposits. |
| Secondary Contaminants | Recommended Level (Non-Health Based Standards) | Likely Source of Contaminants | ||||
| Chloride | ppm | 250 | Average detected: 13.9 | Naturally present, brine from oilfield operations. | ||
| Range detected: 10.5 - 18.2 | ||||||
| pH | su | 6.5 - 8.5 | Range detected: 7.5 - 8.5 | Measure of acidity. Naturally present, adjusted in drinking water treatment. | ||
| Sulfate | ppm | 250 | Average detected: 24.5 | Naturally present in the environment. | ||
| Range detected: 3.96 - 54.0 | ||||||
| Other Required Monitoring | Unit | Recommended Level | Likely Source of Contaminants | |||
| Cryptosporidium | Second round of monitoring (over 48 month duration) was completed in 2017. Detections were found in source water only and were not detected at levels of concern; Cryptosporidium is a microbial pathogen found in surface water throughout the U.S. Although filtration removes cryptosporidium, the most commonly-used filtration methods cannot guarantee 100 percent removal. Our monitoring indicates the presence of these organisms in our source water. Current test methods do not allow us to determine if the organisms are dead or if they are capable of causing disease. Ingestion of cryptosporidium may cause cryptosporidiosis, an abdominal infection. Symptoms of infection include nausea, diarrhea, and abdominal cramps. Most healthy individuals can overcome the disease within a few weeks. However, immuno-compromised people are at greater risk of developing life-threatening illness. We encourage immuno-compromised individuals to consult their doctor regarding appropriate precautions to take to avoid infection. Cryptosporidium must be ingested to cause disease, and it may be spread through means other than drinking water. | |||||
| Sodium | ppm | Standard has not been established. | Average detected: 10.3 | Naturally occurring, urban stormwater runoff or discharge from sewage treatment plants. | ||
| Range detected: 8.36 - 12.4 | ||||||
| UCMR5 Monitoring: The City of Tulsa completed the Unregulated Contaminant Monitoring (UCMR5) in 2023, which required monitoring for Lithium and 29 Per- and Polyfluoroalkyl Substances (PFAS). Unregulated contaminants are those for which EPA has not established drinking water standards. The purpose of unregulated contaminant monitoring is to assist EPA in determining the occurrence of unregulated contaminants in drinking water and whether future regulation is warranted. Results indicate no detectable levels of PFAS and Lithium present in drinking water. | ||||||
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