Honolulu County regulates grading and drainage under ROH Chapter 18A, requiring permits, bonds, and inspections for land alteration across Oahu to protect slopes, streams, and downstream properties.
Chapter 18A is Oahu's grading and drainage code. Article 2 covers permits, bonds, and inspections, with Sec. 18A-2.2 setting grading permit application requirements and Sec. 18A-2.4A specifying penalties for grading without a permit. Article 3 regulates grading, grubbing, and stockpiling, including cut and fill slope ratios, drainage diversion, and revegetation. DPP reviews plans and can require hydrology reports for projects that may affect downstream drainage across the island, from Mililani ridge lots to coastal Hauula parcels. Grading permits typically require posted security bonds for site stabilization.
Grading without a permit can trigger Sec. 18A-2.4A penalties, including doubled permit fees, stop-work orders, civil fines up to $1,000 per day, and restoration requirements for disturbed areas.
Honolulu County, HI
Honolulu County's Building Code Section 16-6.2 requires residential swimming pools on Oahu to be enclosed by compliant fences or protective barriers to preve...
Honolulu County, HI
Honolulu's LUO Section 21-4.40 limits retaining wall heights in required yards to 6 feet when containing fill and combines terraced wall heights for measurem...
Honolulu County, HI
Honolulu's LUO Section 21-4.60 defines 'fence' and governs allowed materials including wrought iron, wire, wood, vinyl, and plastic supported by post foundat...
Honolulu County, HI
Honolulu's Land Use Ordinance Section 21-4.30 defines required yards and street setbacks, including what fences and structures may occupy property lines shar...
Honolulu County, HI
Honolulu County requires building permits for most fences and walls under ROH 18-3.1, though retaining or riprap walls not exceeding 30 inches in height are ...
Honolulu County, HI
Honolulu's Land Use Ordinance Section 21-4.60 limits fence, wall, and hedge heights across zoning districts and imposes additional setback or landscape scree...
See how Honolulu County's grading & drainage rules stack up against other locations.
Help us keep this page accurate. If you notice an error or outdated information, let us know.