Summary of Oklahoma's Water Reuse Guideline or Regulation for Potable Water Reuse
This page is part of the EPA’s REUSExplorer tool, which summarizes the different state level regulations or guidelines for water reuse for a variety of sources and end-uses.
The source water for this summary is Treated Municipal Wastewater.
On this page:
- Technical basis
- Types of planned potable reuse approved for use in Oklahoma
- Potable reuse specifications (table)
- Upcoming state law or policy
- References
- Disclaimer
This page is a summary of the state’s water reuse law or policy and is provided for informational purposes only. Please always refer to the state for the most accurate and updated information.
In Oklahoma, potable water reuse The use of highly treated recycled water for drinking water purposes. This reuse application includes both indirect potable reuse through introduction of recycled water into an environmental buffer such as a surface reservoir or groundwater aquifer, and direct potable reuse through introduction of recycled water into a drinking water system. applications include indirect potable reuse (surface water augmentation and aquifer storage and recovery). The source of water ( treated municipal wastewater Treated wastewater effluent discharged from a centralized wastewater treatment plant of any size. Other terms referring to this source of water include domestic wastewater, treated wastewater effluent, reclaimed water, and treated sewage. ) is specified by the state as municipal wastewater. The write-up uses state terms when discussing sources or uses of water that may differ from the Regulations and End-Use Specifications Explorer's (REUSExplorer's) terms.
Technical basis
Potable water in the United States must meet all applicable Safe Drinking Water Act (SDWA) requirements, including its implementing regulations (40 C.F.R. § 141) for chemical and microbial contaminants and pollutant discharges from a point source for surface water augmentation require a federal National Pollutant Discharge Elimination Systems (NPDES) permit (40 C.F.R. § 122). Additionally, to augment surface water that is part of the Public Water Supply (PWS) with “IPR source water”, an Oklahoma Pollutant Discharge Elimination System (OPDES) permit must be obtained (Okla. Admin. Code § 252:628). Oklahoma defines IPR source water as “water originating from a municipal wastewater treatment facility that meets the benchmarks, treatment, and operational standards” and “has been permitted under an OPDES wastewater permit for release to a surface water source for a PWS system for the purpose of augmenting the flow to an existing PWS system” (Okla. Admin. Code § 252:628). The OPDES permit provides additional protection in addition to NPDES and Oklahoma’s water quality standards (Okla. Admin. Code § 785:45).
Oklahoma indirect potable reuse regulations also require specific treatment requirements for pathogens and chemicals. Microbial (pathogen) log reduction requirements include a five-log Adenovirus type 15 reduction, five-log Salmonella typhimurium reduction, 3-log Giardia lamblia cyst reduction and three-log Cryptosporidium oocyst reduction. Oklahoma also has specific treatment requirements for total coliform (<2 bacteria/100 mL), TSS (≤5 mg/L daily maximum), TDS (≤700 mg/L or two standard deviations above the mean background TDS value of the receiving waterbody), total nitrogen (≤8 mg/L monthly average, ≤12 mg/L daily maximum) and total phosphorus (≤0.2 mg/L monthly average, 0.3 mg/L daily maximum). The technical basis for the removal of microbial and chemical contaminants is not explicitly specified.
Oklahoma also approves the use of reclaimed water for aquifer storage and recovery (ASR). All ASR activities require a permit issued by Oklahoma DEQ and all water, as delivered to the aquifer, must meet the Oklahoma groundwater requirements outlined in Okla. Admin Code § 785:45 for the class of groundwater aquifer that will receive the water and be monitored “in accordance with EPA approved procedures” (Okla. Admin. Code § 252:653).
Types of planned potable reuse approved for use in Oklahoma
Okla. Admin. Code § 252:628 defines the following approved planned potable uses:
- Indirect potable reuse
- Surface water augmentation – the discharge of treated wastewater to a surface waterbody for the purpose of augmentation
- Aquifer storage and recovery – delivery of water into an aquifer for later recovery and use
Potable reuse specifications
Summary of Oklahoma's Potable Reuse Specifications
| Recycled Water Class/Category | Source Water Type | Water Quality Parameter | Specification | Sampling/Monitoring Requirements (Frequency of monitoring; site/ location of sample; quantification methods) |
|---|---|---|---|---|
|
Indirect potable reuse (surface water augmentation) |
Municipal wastewater |
Adenovirus type 15 |
5-log removal |
“Disinfection from the secondary treated effluent to the end of pipe discharge must achieve these log removals” |
|
Salmonella typhimurium |
5-log removal |
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Cryptosporidium |
3-log removal |
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Giardia lamblia |
3-log removal |
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|
Total coliform |
No measurable amount (<2 bacteria/100 mL) |
Monitored daily by grab sample |
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Total residual chlorine (TRC) or total residual oxidant (TRO) |
No measurable amount (<0.1 mg/L) |
Monitored daily |
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|
5-day carbonaceous biochemical oxygen demand (CBOD5) |
≤5 mg/L (daily maximum) |
Monitored in accordance with minimum control test requirements for BOD5 established in Appendix A of Okla. Admin. Code § 252:606. |
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|
pH |
6.5-9.0 |
Monitored in accordance with minimum control test requirements established in Appendix A of Okla. Admin. Code § 252:606. |
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Flow |
Monitoring only |
Monitored continuously |
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Total organic carbon (TOC) |
Monitoring only |
Monitored daily |
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Total suspended solids (TSS) |
≤5 mg/L (daily maximum) |
Shall be monitored in accordance with minimum control test requirements established in Appendix A of Okla. Admin. Code § 252:606. |
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Turbidity |
Turbidity shall not exceed: 2 NTU (daily average), 10 NTU (daily maximum), or 5 NTU (more than 5% of daily maximum per month) |
Monitored continuously |
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Total Dissolved Solids (TDS) |
Effluent limitations for TDS shall be set so the maximum ambient concentration will not exceed the greater of 700 mg/L or two (2) standard deviations above the mean background TDS value of the receiving waterbody prior to IPR Source Water discharge. The calculated permit limit shall be applied as a monthly average permit limit in the OPDES discharge permit. The daily maximum permit limit shall be established as 1.5 times the monthly average permit limits. |
IPR Source Water discharges shall be monitored for these additional conservative parameters monthly. |
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Chlorides |
“Actions and action levels shall be determined by DEQ”. The calculated permit limits shall be applied as monthly average permit limits in the OPDES discharge permit. Daily maximum permit limits shall be established as 1.5 times the monthly average permit limits. |
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Sulfates |
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Aluminum |
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Iron |
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Manganese |
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Total Nitrogen |
8 mg/L (monthly average) 12 mg/L (daily maximum) |
Monitored in the effluent. Nutrient parameters which are included in the permit shall be monitored at a frequency of weekly during the period of May through October and twice a month during the period of November through April. After two years of monitoring, DEQ may reduce monitoring frequencies to twice a month during the period of May through October and monthly during the period of November through April. |
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|
Total Phosphorus |
0.2 mg/L (monthly average) 0.3 mg/L (daily maximum) |
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Indirect potable reuse (Aquifer storage and recovery) |
Municipal wastewater |
All ASR activities require a permit issued by Oklahoma DEQ and all water, as delivered to the aquifer, must meet the Oklahoma groundwater requirements outlined in Okla. Admin. Code § 785:45 for the class of groundwater aquifer that will receive the water and be monitored “in accordance with EPA approved procedures” (Okla. Admin. Code § 252:653). |
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Sources = Okla. Admin. Code § 252:606; Okla. Admin. Code § 252:628; Okla. Admin. Code § 252:653; Okla. Admin. Code § 785:45
Upcoming state law or policy
No upcoming potable reuse regulations were found for Oklahoma.
References:
Aquifer Storage and Recovery, Okla. Admin. Code § 252:653.
EPA-Administered Permit Programs: The National Pollutant Discharge Elimination System, 40 C.F.R. § 122.
Indirect Potable Reuse for Surface Water Augmentation, Okla. Admin. Code § 252:628.
National Primary Drinking Water Regulations, 40 C.F.R. § 141.
Oklahoma Pollutant Discharge Elimination System (OPDES) Standards, Okla. Admin. Code § 252:606.
Oklahoma’s Water Quality Standards, Okla. Admin. Code § 785:45.
Please contact us at waterreuse@epa.gov if the information on this page needs updating or if this state is updating or planning to update its laws and policies and we have not included that information on the news page.