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OK

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Oklahoma Water Quality

537

Utilities in database

3.6M

Residents served

3

With open violations

161

PFAS monitored

Quick Answer

Oklahoma public drinking water is served by 537 EPA-tracked water systems, providing service to approximately 3.6 million residents through public utilities. 3 of those systems currently have open health-based violations on record in the EPA federal database. 161 systems have official PFAS monitoring records from the EPA UCMR 5 program (2023–2025). About 25% of OK residents use private wells, which fall outside federal utility compliance monitoring.

3 Oklahoma water systems have open health-based violations recorded in EPA SDWIS. An open violation means a contaminant exceeded a federal limit and the violation has not been formally resolved in the federal database. Check individual utility pages for current status.

Open Health-Based Violations in Oklahoma

Records sourced from EPA SDWIS. A record may be under review or resolved at the utility level but not yet updated in federal records. Water Utility Report does not determine whether water is safe to drink.

Drinking Water in Oklahoma

Oklahoma has 537 community water systems serving approximately 3.6 million residents. Primary water sources include surface water. The most commonly reported contaminants include disinfection byproducts, nitrates, arsenic. 25% of Oklahoma residents rely on private wells. DEQ holds primary enforcement authority under the Safe Drinking Water Act.

Utilities in Oklahoma

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Key Contaminant Concerns in Oklahoma

These contaminants appear most frequently in Oklahoma utility records or pose elevated risk in this region based on EPA data.

moderate

Nitrates

Nitrate (NO₃⁻) is a nitrogen-containing compound that forms naturally through the decomposition of organic matter. At elevated concentrations — almost always caused by human activity — nitrate is converted in the digestive system to nitrite, which then reacts with hemoglobin to form methemoglobin, a form of hemoglobin that cannot carry oxygen. In the body, nitrite also reacts with amines in food to form N-nitroso compounds (nitrosamines) — known carcinogens classified by the IARC as Group 2A (probable human carcinogens). The United States applies over 23 million tons of nitrogen fertilizer annually, making agricultural runoff the dominant source of nitrate contamination in U.S. groundwater.

EPA limit: 10 mg/L

moderate

DBPs

When utilities add chlorine to water to kill pathogens, it reacts with dissolved organic matter — leaves, algae, soil — to produce disinfection byproducts (DBPs). Over 600 DBPs have been identified. The EPA regulates two groups: total trihalomethanes (TTHMs, including chloroform) and haloacetic acids (HAA5). DBP levels tend to be highest in surface water systems and in warm months when organic matter is elevated.

EPA limit: 80 µg/L (TTHMs) / 60 µg/L (HAA5)

moderate

Arsenic

Arsenic (As) occurs naturally in rock and soil, dissolving into groundwater through natural weathering processes. Inorganic arsenic — the form found in drinking water — is a known human carcinogen. The western United States has particularly arsenic-rich geological formations, but elevated levels have been found in 48 states. Arsenic is tasteless and odorless.

EPA limit: 10 ppb

City Water Reports in Oklahoma

Tap water quality pages for Oklahoma cities — violations, PFAS records, utility profiles, and official source links.

Oklahoma PFAS Watchlist — all utilities with official records

Independent Water Testing

Find a certified lab in Oklahoma

Utility compliance records show what water systems report to the EPA. An independent test from a certified laboratory confirms what's actually in your tap water. Oklahoma labs can test for PFAS, lead, nitrates, bacteria, and dozens of other contaminants.

Explore Water Quality in Oklahoma

Common Questions About Oklahoma Drinking Water

Oklahoma Water FAQs

Data sources: Utility compliance and violation data from EPA SDWIS (Safe Drinking Water Information System). PFAS monitoring records from EPA UCMR 5 (Unregulated Contaminant Monitoring Rule 5, 2023–2025). Contaminant data from EPA and ATSDR public references. This page summarizes public records — it is not a compliance determination. Methodology →

Last updated: 2026-04-22