HAR Chapter 11-62 (Wastewater Systems)
HAR Chapter 11-62 is the Hawaiʻi Department of Health rule that governs wastewater systems — including the design and siting standards for on-site systems like septic tanks and leach fields, and the treatment of cesspools.
Among its provisions, Chapter 11-62 sets vertical-separation requirements — the minimum depth of unsaturated soil a leach field must keep above the water table — so effluent is treated before it reaches groundwater. On low, coastal parcels that buffer is thin, and it shrinks further as groundwater rises with sea level.
The rule is the practical backbone of on-site wastewater feasibility: whether a parcel can support a conventional septic system, needs an aerobic treatment unit, or has to connect to sewer depends heavily on soils, lot size, and separation to groundwater under Chapter 11-62.
For a coastal or high-water-table parcel, HAR §11-62 separation is the difference between a straightforward septic install and a costly one — and, under a sea-level-rise horizon, a system compliant today may not be by mid-century. It's a core feasibility question to screen before committing to a wastewater plan.
HAR Chapter 11-62 requires a minimum vertical separation of unsaturated soil between a leach field and the water table so effluent is treated before reaching groundwater. On low coastal lots that buffer can be marginal.
This is a plain-language reference, not legal advice. KILO is a pre-development screening tool, not a system of record — confirm any determination with the agency of jurisdiction.