HCC §23-92

Storm water and drainage rules for subdivisions

Read the official text at hawaiicounty.gov ↗

This section requires the person developing a subdivision to build a storm water system that keeps runoff from the project inside the subdivision during a heavy rainstorm. The system must use methods that let water soak into the ground, and it must not change drainage patterns in the surrounding area. The developer must also follow other county rules about drainage and flooding.

developers

The ordinance, as written (Hawaiʻi County) — Drainage, flood, and erosion mitigation measures

A copy, taken August 21, 2026. The version published by Hawaiʻi County is the one that governs, and it may have changed since. Check it before relying on anything here.

(a) The subdivider shall construct a storm water disposal system to contain runoff caused by the subdivision improvements within the boundaries of the subdivision, up to the expected one-hour, ten year storm event, as shown in Plate 1 of the Department of Public Works “Storm Drainage Standards”, dated October 1970, or any approved revisions, unless those standards specify a greater recurrence interval, in which case, the greater interval shall be used. The amount of expected runoff shall be calculated according to the Department of Public Works “Storm Drainage Standards”, dated October 1970, or any approved revisions thereto, or by any nationally-recognized method meeting with the approval of the director of public works. Runoff calculations shall include the effects of all required subdivision improvements, and lot improvements that may be allowed by existing zoning. (b) Storm water shall be disposed into drywells, infiltration basins, or other infiltration methods. The subdivision shall not alter the general drainage pattern above or below the subdivision. (c) Subdivider shall also comply with the requirements of chapter 27, Hawai‘i County Code.

Read the official text at hawaiicounty.gov ↗as published Jul 16, 2026our copy taken Aug 21, 2026

Published by the County of Hawaiʻi Office of the County Clerk.

LawTrove is not legal advice. The summary above is a computer-generated restatement — the authoritative text is the official version linked above.