Hawaii Grading Permits: When You Need One and What DPP Requires

When is a grading permit required?

Under ROH Chapter 14 (Grading, Grubbing, and Stockpiling), a grading permit is required when any of the following thresholds are met:

• Excavation or fill of more than 50 cubic yards of material
• Any grading on a slope of 15% or greater
• Any grading within 50 feet of a drainage channel, stream, or body of water
• Any grading that would alter drainage patterns on adjacent properties
• Any land clearing exceeding 5,000 square feet

These thresholds are cumulative for a project — you cannot divide the work into multiple smaller phases to avoid the permit threshold.

Grading plan submittal requirements

A grading permit application requires:

• Topographic site plan showing existing and proposed grades with contours at no more than 2-ft intervals
• Drainage plan showing direction of surface flow, catch basins, and outfall to an approved point
• Erosion and sediment control plan meeting DPP and DOH requirements
• Cut and fill quantities tabulated by section
• Geotechnical report (if triggered by slope, fill depth, or proximity to a structure)

When is a geotechnical report required?

A geotechnical investigation and report stamped by a Hawaii-licensed geotechnical engineer is triggered by:

• Grading on slopes steeper than 15%
• Fill depths exceeding 4 feet
• Excavation adjacent to existing structures
• Sites with expansive soils, filled land, or poor bearing capacity (common near the coasts and former agricultural land)
• Any project in a designated landslide hazard area

The geotechnical report must be coordinated with the structural engineer's foundation design. DPP will not approve grading plans that reference geotechnical recommendations that conflict with the structural design.

Erosion and sediment control

Hawaii receives some of the highest rainfall intensities in the United States. EPA and HDOH require that any land disturbing activity over 1 acre obtain a National Pollutant Discharge Elimination System (NPDES) Construction General Permit from HDOH before beginning grading. Projects under 1 acre of disturbance may still be subject to HDOH requirements if they discharge to a waterway.

Erosion control measures — silt fences, fiber rolls, mulching, and temporary sediment basins — must be installed before grading begins and maintained throughout construction. DPP inspectors check erosion controls at the grading inspection.

Grading and the building permit

Grading for a building foundation can be covered under the building permit rather than a separate grading permit if the scope is limited to the building pad and immediate drainage. Significant earthwork beyond the building footprint — terracing, retaining walls over 4 ft, and drainage improvements — typically requires a separate grading permit even when a building permit is in process.

A common sequencing mistake: starting grading under the building permit before the building permit is issued. Grading can proceed under a separate grading permit before the building permit is approved, but the grading plan must be coordinated with the building foundation design to avoid having to regrade when the building plans are revised.