Summary of Hawai'i's Water Reuse Guideline or Regulation for Rainwater Collected Onsite 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.

• Technical basis
• Onsite non-potable water reuse applications approved for use in Hawai'i
• Water reuse category/type
• Additional context and definitions
• Onsite non-potable reuse specifications
• 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 Hawai'i, 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 domestic non-potable reuse. 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 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

The Hawai’i Department of Health (DOH) promotes and provides guidance on rainwater collection for domestic non-potable reuse (Hawai’i DOH 2020). A permit is not required for the construction, installation, repair or alteration of non-potable water systems. 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. Hawai’i does not provide specific requirements or specifications for the collection of rainwater for onsite non-potable water reuse applications. However, the state does define guidelines for rainwater catchment systems the removal of debris, microbial contaminants, chemicals and other relevant indicators related to onsite non-potable water reuse for Hawai’i (Hawai’i DOH, 2020). The technical basis for developing the specifications and/or removal of debris, microbial contaminants, chemicals and other relevant indicators for these rainwater catchment systems is not explicitly specified. The DOH (2020) believes that the appropriately applied requirements listed in the table should contribute to rainwater catchment system safety for non-potable domestic use.

Onsite non-potable water reuse applications approved for use in Hawai'i

Hawaii does not define specific approved end-use applications and does not explicitly preclude potential non-potable applications (Hawai’i DOH, 2020).

Water reuse category/type

Hawai’i does not assign harvested rainwater used for onsite non-potable water reuse to a category or class, and there are no specific treatment requirements for harvesting rainwater. However, guidance is provided to ensure appropriate water quality for non-potable domestic usage (UH Manoa, 2020).

Additional context and definitions

Hawai’i DOH does not regulate individual rainwater catchment systems (i.e., installed at individual homes). To improve water quality and reduce the need for water treatment, homeowners are advised to properly design, regularly maintain and periodically test their rainwater catchment system. No government agencies oversee rainwater catchment systems in Hawai’i. The Hawai’i Rainwater Catchment Systems Program (2020) provides robust guidelines on water collection, storage, maintenance, treatment and testing for rainwater catchment systems (UH Manoa, 2020). Installing a certified filtration/treatment system to remove contaminants of concern is encouraged.

Screening tests for E. coli, turbidity, lead and copper are encouraged. These water quality analyses should be performed using a certified or DOH-approved laboratory. Water sampling should follow standard protocols for accurate laboratory results, which typically follow EPA Test Methods (referenced in the table). It is recommended that a person with water sampling training takes the samples. The samples must be taken after all water treatment and prior to the intended domestic use. The sample must meet the following Acceptable Levels using the EPA Test Methods specified in the table.

Additional precautions should be taken during periods of increased volcanic activity. Information on these precautions as well as other guidelines for rainwater catchment system operation and maintenance are provided by the Hawai’i DOH (2018).

Onsite non-potable reuse specifications

Summary of Hawai'i's Onsite Non-Potable Water Reuse Specifications

Source = Hawai’i DOH (2020)

* 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 Hawai’i.

References:

Hawai’i Department of Health (DOH). 2018. Precautionary Measures for Residential Rainwater Catchment Users During Volcanic Activity.

Hawai’i DOH. 2020. Rainwater Catchment.

University of Hawai’i at Manoa (UH Manoa). 2020. Rainwater Catchment Systems for Hawai’i.

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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.