Summary of North Carolina’s Water Reuse Guideline or Regulation for Landscaping and 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.

• Technical basis
• Onsite non-potable reuse approved for use in North Carolina
• Water reuse category/type
• Additional context and definitions
• Onsite non-potable reuse specifications (table)
• Upcoming state law or policy
• References
• Disclaimer

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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 North Carolina, landscaping water reuse for landscapingThe use of recycled water on land to assist in the irrigation of vegetation in residential and non-residential areas. Includes impoundments to store water for irrigation , ornamental vegetation, parks, school yards, sporting facilities (including golf courses), private gardens, roadsides and greenbelts, and cemeteries. Excludes irrigation of areas used for agriculture, commercial reuse applications, or any centralized non-potable reuse. reuse applications include outdoor irrigation, and onsite non-potable water reuse 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. applications include decorative fountains, yard hydrants, vehicle washing, hose bibs, toilet and urinal flushing, trap primers, fire suppression systems, clothes washers and outdoor pools. The source of water (rainwater collected onsite) rainwater collected onsite Precipitation collected at the district or regional scale is classified separately under 'stormwater.' is specified by the state as untreated rainwater and treated 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.

Technical basis

North Carolina approves the use of non-potable rainwater collection and distribution systems for onsite non-potable water reuse applications in residential and commercial buildings (N.C. Gen. Stat. § 143). Untreated rainwater applications include outdoor irrigation, decorative fountains, yard hydrants (i.e., outdoor water spigots), vehicle washing and outdoor hose bibs (NCPC, 2018). Treated water applications include toilet and urinal flushing, trap primers, fire suppression systems, clothes washers, residential hose bibs and outdoor pools and spas (NCPC, 2018). 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. In North Carolina, a permit is required for the construction, installation, alteration and repair of all non-potable water systems, including rainwater harvesting systems (NCPC, 2018). Treatment requirements and performance standards 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 North Carolina

The North Carolina Plumbing Code (NCPC, 2018) defines the following specific onsite non-potable water reuse applications for untreated rainwater from non-potable water systems:

• Outdoor irrigation
• Decorative fountains
• Yard hydrants
• Vehicle washing
• Outdoor hose bibs not routed through building wall

The NCPC (2018) defines the following specific onsite non-potable water reuse applications for treated rainwater from non-potable water systems:

• Toilet flushing
• Urinal flushing
• Evaporative cooling tower make-up
• Trap primers
• Fire suppression systems
• Clothes washers
• Outdoor pools and spas
• Residential hose bibs

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

North Carolina does not assign harvested rainwater used for onsite non-potable water reuse to a category or class. North Carolina permits harvested rainwater for onsite non-potable water reuse applications, divided by whether the collected rainwater is treated or untreated. Additional water quality requirements may apply dependent on the intended application.

Specific treatment requirements are provided for non-potable water systems; however, these requirements are not specific to the use of harvested rainwater for onsite non-potable water reuse applications and apply to non-potable reuse applications with other source water types. Briefly, these treatment requirements include:

• Filtration: All non-potable rainwater catchment systems must include a debris excluder or equivalent device to prevent debris from entering the storage tank. Collected rainwater must be further filtered as required for the intended end use (NCPC, 2018). Specifically, non-potable water utilized for water closet and urinal flushing must be filtered by a 100-micron or finer filter (NCPC, 2018). All filtration must have a mechanism to indicate servicing or replacement as well as be installed with shutoff valve immediately upstream and downstream to allow for maintenance (NCPC, 2018).
• Disinfection: North Carolina requires harvested rainwater be disinfected as necessary to meet water quality requirements specific for the intended onsite water reuse application, including the minimum treatment requirements provided in the table (NCPC, 2018).
• Insects and vermin: All storage tanks must be protected to prevent entrance of insects and vermin into the tank and piping system. Screens installed on vent pipes, inlets and overflow pipes must have an aperture less or equal to one sixteenth an inch (1.6 mm) and be close-fitting (NCPC 1301.7). North Carolina provides guidance and encourages further measures towards mosquito controls through system design methods including screening or sealing points of entry, installing a tank in a cooler location or routine maintenance (NCSE, 2021).

Additional context and definitions

In North Carolina, collection of rainwater should be limited to above-ground waterproof roofing surfaces (NCPC, 2018). Collection of rainwater for onsite reuse from vehicular parking or pedestrian surfaces is prohibited, unless the rainwater is solely used for landscape irrigation (NCPC, 2018). Collection from surface, roof gutters and downspouts must be constructed from approved materials as to meet the rainwater quality for the desired end use (NCPC, 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 (NCPC, 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 (NCPC, 2018). Cleanouts must be provided in the rainwater collection system to allow access to all filters, flushes, pipes and downspouts (NCPC, 2018).

North Carolina requires specific design elements when implementing rainwater collection practices. Non-potable water storage tanks may be either above or below grade (NCPC, 2018). Above grade storage tanks must be protected from direct sunlight by using opaque, UV-resistant materials, having specially constructed sun barriers or being painted to prevent algae growth (NCPC, 2018). Below grade storage tanks must not be located under soil piping, waste piping or any potential source of contamination (NCPC, 2018). 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 (NCPC, 2018).

All non-potable water storage tanks must be made identifiable with purple piping, embossing or signage with the words “Nonpotable water is utilized for [application name]. CAUTION: NONPOTABLE WATER – DO NOT DRINK.” (NCPC, 2018). Further, all non-potable water utilized for indoor onsite uses must be colored blue or green (NCPC, 2018).

Onsite non-potable water reuse specifications

Summary of North Carolina's Onsite Non-potable Water Reuse Specifications

Source = NCPC (2018)

* Information about sampling and monitoring requirements such as frequency, site and quantification methods not specifically listed in the table was not explicitly specified in the State-specific regulations.

Upcoming state law or policy

No upcoming onsite non-potable water reuse regulations related to rainwater were found for North Carolina.

References:

Clean Water Act, 33 U.S.C. §§ 1251 et seq.

North Carolina Department of Environmental Quality (NCDEQ). 2020. Stormwater Design Manual: Appendix C-7. Rainwater Harvesting.

North Carolina Plumbing Code (NCPC). 2018. Chapter 13: Nonpotable Water Systems.

North Carolina State Extension (NCSE). 2021. Mosquito Control for Rainwater Harvesting Systems.

NCSE. 2021. Rainwater Harvesting: Guide for Homeowners.

Session Law 2009-243: House Bill 749, N.C. Gen. Stat. § 143.

Water Reuse; Policy; Rulemaking, N.C. Gen. Stat. § 143-355.5 (2022).

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Disclaimers

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.