Latest Testing Results

• Lead Levels: The 2024 testing cycle recorded a 90th percentile lead level of 4.1 parts per billion (ppb) — well below the EPA action level of 15 ppb (and the incoming LCRI action level of 10 ppb from November 2027). Individual results ranged from 0 to 14.62 ppb. OKC treatment plants deliver lead-free water; any lead detection is from private-side service lines or older internal plumbing. Copper came in at 0.2016 ppm at the 90th percentile, also below its 1.3 ppm action level.
• Testing Scope: Oklahoma City is required to test a minimum of 240 samples per month under the Total Coliform Rule. In May 2024, 2.08% of monthly coliform samples returned positive — triggering follow-up testing as required, with no confirmed violations. PFAS monitoring under UCMR 5 detected PFPeA at an average of 1.3 ppt — below the 4 ppt EPA limit. Lithium was also detected at an average of 42.6 µg/L. Check our national water quality checker for broader comparisons.
• Compliance Status: Oklahoma City’s water met or exceeded all federal and state drinking water standards in 2024, maintaining full compliance with EPA and Oklahoma Department of Environmental Quality regulations — zero violations recorded for the calendar year.

Diverse Water Sources

• Lake Hefner & Lake Overholser: Primary sources located within Oklahoma City, fed by the North Canadian River. These surface water sources accumulate naturally occurring minerals, agricultural runoff, and seasonal algae that can affect taste and odour — and contribute organic matter that reacts with disinfectants to form byproducts.
• Draper Lake (Atoka Pipeline): A major source fed by the Atoka pipeline, which transports water from Lake Atoka in southeastern Oklahoma, providing access to water from less-developed watersheds. This long-distance supply is a key component of OKC’s drought resilience strategy.
• Canton Lake & Supplemental Sources: Sardis Lake and Canton Lake serve as additional sources during peak demand and drought conditions, providing system resilience. This diversity of supply is a key strength of OKC’s water security strategy.

Treatment Technology

• Dual Treatment Plants: The Hefner and Draper Water Treatment Plants use conventional treatment processes — coagulation, sedimentation, filtration, and chloramine disinfection — to ensure effective pathogen control across the service area.
• Chloramine Disinfection: Both plants use chloramine (chlorine plus ammonia) as the primary disinfectant, maintained at a monthly average of 3 mg/L. This provides longer-lasting residual protection in the distribution system compared to chlorine alone, but creates disinfection byproducts including trihalomethanes and haloacetic acids.
• Contaminant Challenges: Despite effective pathogen control, independent testing shows disinfection byproducts exceed EWG health guidelines significantly — trihalomethanes at a running annual average of 69 ppb against an EWG health guideline of 0.15 ppb, and haloacetic acids at 36 ppb against an EWG guideline of 0.1 ppb. Residents wanting additional protection should consider NSF-certified home filtration.

Infrastructure Development (2025–2026)

• Lead-Safe OKC Programme: The city’s service line inventory — covering all ~254,000 service accounts — identified 173 public-side lead lines (0.07% of accounts). Annual notification letters are sent to customers with lead or unknown-status service lines by December 31 each year as required under EPA’s Lead and Copper Rule Revisions (LCRR). Residents can check their line status at okc.gov/leadsafe through the Lead-Safe Community Database.
• Service Line Replacement Plan: OKC is developing a formal lead service line replacement plan, due by the EPA’s LCRI compliance deadline of November 1, 2027. Under the LCRI, all public-side lead service lines must be replaced within 10 years of that date, and the action level for lead will drop from 15 ppb to 10 ppb. The 2024 lead action level is 15 ppb and OKC’s 90th percentile result of 4.1 ppb is well within that limit. No federal or state funding is currently available for private-side replacements.
• Advanced Monitoring: Enhanced real-time water quality sensors and expanded testing protocols are in use to detect emerging contaminants and maintain regulatory compliance across the distribution network. For national alerts and emerging issues, see our live boil water notices tracker.

Customer Support Programmes

Oklahoma City provides extensive customer support including free basic water quality testing for residents with taste, odour, or quality concerns. The H2O Access programme offers financial assistance for water bill payments, while conservation programmes promote efficient use through rebates and education. The city maintains transparent water quality reporting through annual Consumer Confidence Reports at okc.gov/ccr (hard copies available at metro-area libraries). Residents concerned about disinfection byproducts, chromium-6, or lead detected above health guidelines should consider NSF-certified filtration — see our water filter solutions guide for options matched to OKC’s contaminant profile. Stay up to date with local water safety issues through our water alert news section.