HI SB547

Establishes a water conservation income tax credit for taxpayers who install NSF/ANSI 350-certified gray water recycling systems or NSF P343-compliant atmospheric water generators, with residential credits at 25% of installation costs up to $10,000 and commercial credits at 20% up to $50,000.

Provides enhanced tax credit of 35% up to $12,500 for low-income homeowners (adjusted gross income at or below 80% of area median income) who install qualifying water conservation systems.

Requires the Department of Business, Economic Development, and Tourism to establish a rebate program offering 30% of residential installation costs (up to $7,500) and 25% of commercial installation costs (up to $35,000), with 40% rebates up to $10,000 for low-income homeowners.

Mandates the State Building Code Council adopt the International Association of Plumbing and Mechanical Officials' 2023 water efficiency and sanitation standard to regulate design, installation, and maintenance of gray water recycling systems and atmospheric water generators.

Applies the tax credit to taxable years beginning after December 31, 2025; beginning July 1, 2028, only fully NSF P343-certified atmospheric water generators qualify for credits and rebates.