Counties should allow rainwater catchment systems to expand housing options

March 19, 2026, 3 p.m.
Hawaii State Capitol
Conference Room 224 and Videoconference

To: Senate Committee on Energy and Intergovernmental Relations
      Sen. Glenn Wakai, Chair
      Sen. Stanley Chang, Vice-Chair

      Senate Committee on Water, Land, Culture and the Arts
      Sen. Chris Lee, Chair
      Sen. Lorraine R. Inouye, Vice Chair

From: Grassroot Institute of Hawaii
Ted Kefalas, Director of Strategic Campaigns

RE: TESTIMONY IN SUPPORT OF HB1728 HD1 — RELATING TO RAINWATER CATCHMENT SYSTEMS

Aloha Chairs, Vice Chairs and other Committee Members,

The Grassroot Institute of Hawaii supports HB1728 HD1, which would require the counties to allow the installation and use of rainwater catchment systems in all areas.

This bill would give Hawaii residents the opportunity to use rainwater for drinking water and irrigation, and it could help them overcome a barrier to expanding their homes or building small, accessory dwelling units on their properties.

Right now, tens of thousands of Hawaii residents — especially in rural areas — rely on catchment systems for their drinking water.[1] But regulations can make it difficult or impossible to construct a catchment system in areas that have access to a public water system, even if that water system is at capacity and cannot service any additional homes.

This is the situation across much of Kauai, where public water systems do not have the capacity to handle more users, but rainwater catchment is prohibited.[2]

Thank you for the opportunity to testify.

Ted Kefalas
Director of Strategic Campaigns
Grassroot Institute of Hawaii
1050 Bishop St. #508 | Honolulu, HI 96813 | 808-864-1776 | info@grassrootinstitute.org

[1] Patricia Macomber, “Guidelines on Rainwater Catchment Systems for Hawai‘i,” College of Tropical Agriculture and Human Resources, University of Hawai‘i at Mānoa, 2020, p. 3.
[2] Jonathan Helton, “Kauai lawmakers should revisit water catchment issue,” The Garden Island, Sept. 20, 2025.

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