Summary of Hawai'i's Water Reuse Guideline or Regulation for Industry

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
Water reuse industrial applications approved for use in Hawai'i
Water reuse treatment category for industrial applications
Additional context and definitions
Water reuse for industrial applications 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 Hawai'i, includes reuse for certain types of cooling water, boiler feed water, industrial processes and cooling for air conditioning systems. The source of water is specified by the state as municipal wastewater. The write-up on this page 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

Hawai'i approves the use of recycled water for industrial applications, including cooling of power equipment, boiler feed water, industrial processes, industrial cooling, cooling in air conditioning systems (Hawai'i State DOH, 2016b). 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. Treatment requirements and performance standards are applied for the removal of microbial contaminants, chemicals and other relevant indicators related to industrial applications and are summarized in the table. Hawai'i used California’s Title 22 Water Recycling Criteria (Cal. Code Regs. tit. 22) to determine acceptable filtration and disinfection units. The technical basis for other specifications and/or removals of microbial contaminants, chemicals and other relevant indicators is not explicitly specified.

Water reuse industrial applications approved for use in Hawai'i

Hawai'i State DOH (2016b) defines the following approved industrial applications:

Cooling of power equipment while cutting, coring or drilling pavements, walls and other hard surfaces (R-1)
Boiler feed water (R-1)
Industrial processes and industrial cooling (R-1)
Cooling in air conditioning systems (R-1)

Water reuse treatment category for industrial applications

The various classes of treatment for recycled water are defined by their level of treatment (Hawai'i State DOH, 2016b).

For R-1 recycled water, wastewater must be oxidized, filtered and disinfected. The limits specified in the table are set based on system size. Filtration standards are based on the specific technology used.
- Disinfection may be achieved by chlorination, UV or another method that, when combined with filtration, has demonstrated inactivation and/or removal of 99.999% of plaque-forming units of F-specific bacteriophage MS2, polio virus or another virus that is at least as resistant to disinfection as the polio virus.

Additional context and definitions

Hawai'i defines recycled water as “treated wastewater that by design is intended or used for a beneficial purpose” (Haw. Code R. § 11-62). "Industrial Cooling" means cooling of material or air for industrial purposes but excludes air conditioning used for human comfort (Hawai'i State DOH, 2016b).

Components of recycled water systems such as piping, valves, valve covers, etc., must be identified to distinguish them from potable water systems, preferably by being purple in color (Pantone 512 or equal). Where color identification is not feasible, components should be labeled with the words “Recycled Water,” “Recycled Water – Do Not Drink,” or similar (Haw. Code R. § 11-62). Signage must also be posted with both written and pictorial warnings that indicate the quality of the recycled water, its end use and an appropriate warning against human consumption and/or what to do if contact occurs. Signs must be posted in clear view of the public along the border of and within the use area with a recommended maximum spacing of 250 feet between signs.

Water reuse for industrial applications specifications

Summary of Hawai'i’s Water Reuse for Industrial Applications 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)*
R-1 recycled water (Cooling of power equipment while cutting, coring or drilling pavements, walls and other hard surfaces; Boiler feed water; Industrial processes; Industrial cooling; Cooling in air conditioning systems)	Municipal wastewater	5-day biochemical oxygen demand (BOD5)	≤5 mg/L (recommended target) ≤30 mg/L (monthly composite average for large non-pond systems) ≤60 mg/L (single sample maximum, all systems)	Weekly sampling for systems with average daily flow of ≥100,000 gallons/day; monthly sampling for <100,000 gallons/day
		Total suspended solids (TSS)
		Turbidity (for media filtration)	≤2 NTU (24-hour average) ≤5 NTU (exception maximum of 72 minutes within a 24-hour period) ≤10 NTU (single sample maximum)	Continuous monitoring both prior to filtration and after filtration but before disinfection
		Turbidity (for membrane filtration)	≤0.2 NTU (exception maximum of 72 minutes within a 24-hour period) ≤0.5 NTU (single sample maximum)
		Turbidity (for reverse osmosis)
		Total chlorine residual^a (CT)	≤450 mg-min/L at all times ≥90 minutes (modal contact time) Equivalent to 5 mg/L residual chlorine at all times	Continuous monitoring
		UV disinfection^b (for media filtration)	≥100 mJ/cm² (design dose under maximum daily flow) ≥55% (transmittance at 254 nm)	Not specified
		UV disinfection^b (for membrane filtration)	≥80 mJ/cm² (design dose under maximum daily flow) ≥65% (transmittance at 254 nm)
		UV disinfection^b (for reverse osmosis)	≥50 mJ/cm² (design dose under maximum daily flow) ≥90% (transmittance at 254 nm)
		F-specific bacteriophage MS2	99.999% removal (PFU)	Not specified
		Polio virus	99.999% removal	Not specified
		Another virus at least as resistant to disinfection as the polio virus	99.999% removal	Not specified
		Fecal coliforms	≤2.2 per 100 mL (7-day median) ≤23 per 100 mL (30-day single sample maximum) ≤200 per 100 mL (single sample maximum)	Daily; may be reduced to weekly under certain conditions

Source = Haw. Code R. § 11-62; Hawai'i State DOH (2016a)

^* 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.

^a a Where chlorination is used for disinfection.

^b Where UV is used for disinfection. The minimal acceptable design requirements and commissioning of new UV disinfection systems shall comply with the latest Ultraviolet Disinfection Guidelines for Drinking Water and Water Reuse prepared by the National Water Research Institute and Water Research Foundation that has been accepted for use by the Hawai'i Department of Health; a UV system that is Title 22 certified by California is also acceptable.

Upcoming state law or policy

No upcoming regulations related to water reuse for industry were found for Hawai'i.

References:

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

Hawai'i State Department of Health (DOH) Wastewater Branch. 2016a. Reuse Guidelines Volume 1: Recycled Water Facilities.

Hawai'i State DOH Wastewater Branch. 2016b. Reuse Guidelines Volume 2: Recycled Water Projects.

Wastewater Systems, Haw. Code R. § 11-62.

Disclaimers

Please contact us at [email protected] 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.