Cesspool conversion on Oahu

Oahu at a glance

• About 7,491 cesspools, roughly 2.2% of Oahu homes (CCWG final report, Table 1).
• Oahu has the smallest count but the highest share of urgent ones: 64% Priority 1, 22% Priority 2, 14% Priority 3 (CCWG briefing).
• Priority 1 areas include the Windward coast from Kahaluu to Kahuku and the North Shore from Sunset Beach to Haleiwa, with pockets in Kailua, Waimanalo, Ewa Beach, Makaha, Mokuleia and Waialua (Star-Advertiser).
• By ZIP code, the largest clusters in the state HCPT cesspool data are 96712 Haleiwa, 96706 Ewa Beach, 96792 Waianae, 96791 Waialua and 96744 Kaneohe/Kahaluu.

Funding on Oahu

• Statewide loans (Act 120, 2026): low-interest or forgivable loans for low- and moderate-income homeowners, run by the Hawaii Green Infrastructure Authority. Not yet accepting applications (DOH).
• No Oahu-specific grant is currently available.

Check your property's priority on the Hawaii Cesspool Prioritization Tool.

New to this? Start with Cesspool 101.