Oklahoma Wastewater Variances regulations & environmental compliance analysis

Oklahoma Wastewater Variances: What you need to know

Governing Law and Regulations

Water quality variances: Oklahoma Administrative Code (OAC) 785:45-5-4 and OAC 252:606-5-4

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Well construction: OAC 785:35-7-3

Regulatory Agencies

Oklahoma Department of Environmental Quality (DEQ) Water Quality Division

Oklahoma Water Resources Board (Board)

U.S. Environmental Protection Agency (EPA) Region 6

See ADDRESSES & CONTACTS for addresses and telephone numbers.

See national section for basic information and federal regulations.

Comparison: State vs. Federal

Rules. Oklahoma has adopted by reference federal regulations that allow variances from effluent limitations, including thermal discharge variances and fundamentally different factors variances to pretreatment standards under the Oklahoma Pollutant Discharge Elimination System permit program. See the national sections PRETREATMENT STANDARDS and WASTEWATER VARIANCES for more information.

Administration and enforcement. DEQ's Water Quality Division administers and enforces the state's water quality program and makes variance determinations. EPA must approve all variances to water quality standards.

State Requirements


OAC 785:45-5-4 and OAC 252:606-5-4

For purposes of permitting discharges for attainment of numerical criteria, stream flows of the greater of 1.0 cfs or 7Q2 and complete mixing of effluent and receiving water must be used to determine appropriate limits, unless otherwise provided in the state Water Quality Standards.

When numerical criteria do not apply, in-stream conditions, including dissolved oxygen concentrations, organoleptic compounds, nutrients, and oil and grease, must be maintained to prevent nuisance conditions caused by human activities.

Narrative criteria listed in OAC ...

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