Summary of Oklahoma’s Water Reuse Guideline or Regulation for Onsite Non-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 Rainwater Collected Onsite.
On this page:
- Technical basis
- Onsite non-potable water reuse applications approved for use in Oklahoma
- Water reuse treatment category/type
- Additional context and definitions
- Onsite non-potable water reuse specifications
- 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, onsite non-potable water reuse The use of treated onsite collected waters for non-potable purposes at the single-building or district scale. This reuse application excludes the use of recycled water from a centralized treatment and distribution system for landscape irrigation or commercial uses. include fire protection systems. The source of water rainwater collected onsite Precipitation collected at the district or regional scale is classified separately under 'stormwater.' is specified by the state as rainwater. 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.
Check out Oklahoma's other onsite non-potable water reuse summary!
State requirements for water quality and treatment are often associated with the source water. Oklahoma has an onsite non-potable water reuse summary page where the source water is onsite collected waters.
Technical basis
Oklahoma approves the use of harvested rainwater for onsite non-potable water reuse applications, including fire protection systems. All non-potable rainwater collection and distribution systems must abide by the minimum standards set by the Plumbing Code 2018 of Oklahoma (PCO, 2018; Okla. Stat. tit. 59 § 1000.23). All applicable provisions of the Clean Water Act (CWA) (33 U.S.C. §§ 1251 et seq.), including its implementing regulations, must be met in addition to any state water quality standards. A water right permit is not required for collection of water for non-potable domestic use, including that of rainwater (Okla. Stat. tit. 785; OWRB, 2023). Treatment requirements are applied for the removal of debris, microbial contaminants, chemicals and other relevant indicators related to onsite non-potable water reuse are summarized in the table. The technical basis for developing the specifications and/or removal of debris, microbial contaminants, chemicals and other relevant indicators is not explicitly specified.
Onsite non-potable water reuse applications approved for use in Oklahoma
The PCO (2018) defines the following specific onsite non-potable water reuse applications for rainwater harvesting systems:
- Fire protection systems, assuming accordance with the International Fire Code
Additional onsite non-potable water reuse applications for untreated and treated rainwater from rainwater collection and distribution systems are not specified.
Water reuse treatment category/type
Oklahoma does not assign harvested rainwater used for onsite non-potable water reuse to a category or class but specifies that the rainwater collection and distribution system must maintain the minimum water quality standards specific to the desired end use.
Collected rainwater must be filtered and disinfected as required for the intended end use (PCO, 2018). The following requirements are specified for all rainwater collection and distribution systems:
- Filtration: Filtration mechanisms for rainwater in the form of a debris excluder and automatic first-flush diverter, both installed with proper design for clean-out, are required (PCO, 2018).
- Disinfection: Treatment devices must be provided with access for inspection, maintenance and cleanout. A method for indicating servicing or replacement must be established for treatment devices. When chlorine is used for treatment, water must be tested for residual chlorine in accordance with ASTM D1253 and not exceed 4 mg/L (PCO, 2018).
Additional context and definitions
Rainwater collection must be limited to above ground waterproof roofing surfaces and, where approved, vehicular parking or pedestrian walking surfaces (PCO, 2018). Collection surface, roof gutters and downspouts must be constructed from approved materials to meet the water quality required for the desired end use (PCO, 2018). Downspouts and leaders must be connected to a debris excluder or equivalent device that is designed to remove leaves, sticks, pine needles and similar debris to prevent such from entering the storage tank (PCO, 2018). The roof gutters and downspouts must have a continuous slope greater or equal to an eighth of an inch per foot towards the collection inlets and not permit the pooling of water at any point along the slope (PCO, 2018). Cleanouts must be provided in the rainwater collection system to allow access to all filters, flushes, pipes and downspouts (PCO, 2018).
Non-potable water storage tanks should be protected from direct sunlight through one of the following methods: (1) outer tank materials made of UV resistant materials; (2) specially constructed sun barriers; or (3) tank installation in garages, crawl spaces or sheds. Non-potable water storage tanks must be made with durable, nonabsorbent and corrosion-resistant materials compatible with any disinfection system to maintain water quality, among other specifications (PCO 2018). All non-potable water storage tanks must be made identifiable with signage with the words “Nonpotable water is utilized for [application name]. CAUTION: NONPOTABLE WATER – DO NOT DRINK” (PCO, 2018).
Onsite non-potable water reuse specifications
None.
Upcoming state law or policy
No upcoming onsite non-potable water reuse regulations related to rainwater were found for Oklahoma.
References:
Clean Water Act, 33 U.S.C. §§ 1251 et seq.
House Bill (HB) 3055. 2012. Water for 2060 Act.
Plumbing Code of Oklahoma (PCO). 2018. Chapter 13 Nonpotable Water Systems.
Oklahoma State University (OSU) Extension. 2017. Design of Rainwater Harvesting Systems in Oklahoma.
Oklahoma Uniform Building Code Commission, Okla. Stat. tit. 59 § 1000.23 (2016).
Oklahoma Water Resources Board (OWRB). 2023. Water Use Permitting.
Oklahoma Water Resources Board, Okla. Stat. tit. 785.
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.