TMK guide · Land rules
Cesspool conversion (Act 125)
State law requires cesspools to be upgraded, converted or connected to sewer by 2050.
Act 125 of 2017 amended HRS 342D-72 to require every cesspool in Hawaiʻi to be upgraded, converted to an approved system, or connected to sewer by January 1, 2050, with limited exemptions. Bills in the 2026 session proposed phasing that date by priority; check with the Department of Health for the rule in force.
Cesspools put untreated wastewater into the ground. The Department of Health ranks areas by how much harm they do to drinking water, streams and the ocean, and the highest priority areas are expected to convert first.
Some sales now come with questions about the cesspool. A lot on sewer has nothing to convert.
What the law says, and who keeps it
What the ParcelSheet card shows
Whether the lot is on sewer or on an on-site system, and the State records of cesspools and on-site wastewater near the lot where the State publishes them.
Who to ask
The State Department of Health Wastewater Branch, and the County for a sewer connection.
See it on a real lot
- TMK 3-2-4-024-162, Hilo, Hawaiʻi Island
- TMK 4-4-2-016-063, Kapaʻa, Kauaʻi
- TMK 2-2-3-010-014, Pukalani, Maui
Checked 2026-10-17. This page explains a term in plain words. It is not legal advice; the County or State office named above decides.
More land rules
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- Sea level rise exposure area
- Lava flow hazard zones 1 to 9
- CPR lots (condominium property regime)
- ʻOhana units and accessory dwelling units
- Shoreline setback
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- Conveyance tax
- Property tax classes by County
- TMK (Tax Map Key)