Maui County Updates Water Fixture Rules – What Buyers, Sellers & Owners Should Know

In a major move for Maui property owners and real estate professionals, Bill 146 (2024) was passed by the Maui County Council to modernize how water usage is calculated for home expansion, accessory dwellings, and permit applications. Effective January 1, 2026, this change eliminates the outdated “fixture count” system and shifts to gallons-per-day (GPD) water usage projections.

This opens new possibilities for ʻohana units, ADUs, home additions, and even farm structures, especially in upcountry or water-restricted areas.

What’s Changing – From Fixture Units to Water Usage Projections

Previously, the County limited water capacity based on fixture units assigned to sinks, toilets, dishwashers, etc., an outdated system from 1995.

Previous Fixture Unit Limits:           

• 5/8″ meter (Meter Size) - 31 (up to 42)( Max Fixture Units) - $389/unit(Add-on Fixture Cost)
• 3/4″ meter (Meter Size) - 53 (up to 67)( Max Fixture Units) - $356/unit(Add-on Fixture Cost)
• 1″ meter    (Meter Size) - 128 (up to 160)( Max Fixture Units) - $261/unit(Add-on Fixture Cost)

These limits constrained home improvements unless owners paid for added units or upsized meters, often a costly and slow process.

New Policy Highlights (Bill 146, 2024):

• Fixture unit tables eliminated; planning will now be based on GPD water use projections
• No cap on fixture count, as long as projected daily use remains within capacity
• Applies to both new construction and renovations, including ʻohana and farm dwellings
• Officially takes effect on January 1, 2026, with preparation underway in 2025

📄 Read Bill 146 – Council Press Release »

📰 See Maui News Article on the Update »

📚 Op-Ed: Why Plumbing Reform Matters »

What This Means for Property Owners

• Buyers: You may be able to add more fixtures, rooms, or ADUs without needing a second meter
• Sellers: Homes once limited by plumbing can now be more marketable and permit-ready
• Owners: Easier and less expensive to remodel bathrooms, kitchens, or build legally permitted units

New Planning Tool – Water Meter Sizing Worksheet

To help property owners estimate their water usage under the new policy, the Maui Department of Water Supply provides a:

📄 Residential Water Meter Sizing Worksheet (PDF)

This worksheet replaces old fixture tables by calculating water demand in gallons per day (GPD). It includes:

• Unit-specific GPD estimates for bathrooms, laundry, kitchens, hose bibs
• Charts for planning shared use between dwellings
• Planning support for licensed contractors and owner-builders

🛠️ Visit the Maui Department of Water Supply »

Who Benefits Most?

• Homeowners with old meters, especially in Upcountry Maui
• Buyers purchasing with plans to add an ʻohana, ADU, or home office
• Sellers with previously underbuilt lots or CPR units

➡️ Explore Maui CPR Property Types »

➡️ Learn How ʻOhana Units Work on Maui »

➡️ Check the Upcountry Water Meter Priority List »

📅 Timeline & Next Steps

      Step         Date

Bill Passed -    January 2025

County Staff Implementation Prep - Through 2025

New Policy Effective - January 1, 2026

We recommend reviewing your development or renovation plans in 2025, so you’re ready to move forward when the new rule takes effect.

📞 Have Questions? We’re Here to Help.

This water policy change is one of the most owner-friendly updates Maui has seen in years, and it’s a huge opportunity for smart buyers and sellers.

Call us at 808-271-8832

📨 Or contact us here to speak with a local advisor about how these changes affect your property or future purchase.