Rainwater catchment could increase housing on Kauai

The following testimony was submitted by the Grassroot Institute of Hawaii for consideration by the Kaua‘i County Council on Oct. 18, 2023.

October 18, 2023
8:30 a.m.
Kauai County Council Chambers

To: Kaua‘i County Council
      Councilmember Mel Rapozo, Chair
      Councilmember KipuKai Kuali‘i, Vice Chair

From: Grassroot Institute of Hawaii
           Jonathan Helton, Policy Researcher

RE: Resolution 2023-64 — Recommending the Kaua‘i Board of Water Supply Amend Rules and Regulations to Allow Rainwater Catchment Systems on Agricultural Properties

Comments Only

Dear Chair and Councilmembers:

The Grassroot Institute of Hawaii would like to offer its comments on Resolution No. 2023-64, which would encourage the Kauai Department of Water to amend its rules to allow rainwater catchment systems on agricultural properties.

Rainwater collection systems harness rooftops and gutters to collect water that can later be used for irrigation purposes. If the rainwater is filtered or otherwise cleaned, it can also be used as potable water for common household purposes.

This resolution offers an innovative, simple-to-understand change to the county’s water infrastructure policy. Authorizing rainwater collection systems would remove a primary roadblock to new housing construction: costly water infrastructure upgrades.

New water pipes and water meters require significant upfront costs that must be paid by either the homebuilders — which inflates the price they charge for the house — or county taxpayers, who pay for new infrastructure at the expense of other county services. Furthermore, water pipes require ongoing maintenance, creating a constant need for service cuts or tax increases.

Rainwater collection systems, on the other hand, are maintained by the home occupant and do not strain the county budget.

These systems are common and encouraged throughout the state. Maui County has given away free 50-gallon rain barrels for several years,[1] while Honolulu’s Board of Water supply offers a $40 rebate to those who buy rain barrels.[2]

Meanwhile, the Hawaii County Department of Water Supply explicitly says it “does not recognize or regulate rainwater catchment,”[3] although thousands of county residents have such systems.[4]  Likewise, the county water codes in Honolulu, Maui and Kauai are silent on catchment systems.

In light of this, the resolution before the Council should emphasize that the Department should keep regulation minimal so as not to undermine the Council’s intent of encouraging rain collection.

Department of Water rules for catchment systems may indeed encourage their use, but they could have the unintended effect of discouraging residents from collecting rainwater if permits, fees or registration requirements are mandated for all catchment systems.

Further, the Institute does not see any reason Department of Water rules should be limited to incentivizing greater rain collection only on agricultural lands; instead, rain collection should be encouraged in all zones unless there a clear public health reason would dictate otherwise.

Overall, Grassroot believes greater use of rainwater collection will help lower housing prices and county infrastructure costs and promote self-sufficiency and conservation.

Thank you for this opportunity to testify.


Jonathan Helton
Policy Researcher
Grassroot Institute of Hawaii

[1]Rain Barrel Catchment Program Giveaway,” Maui County Department of Water Supply, accessed Oct. 13, 2023.

[2]Residential rebates,” Honolulu Board of Water Supply, accessed Oct. 13, 2023.

[3]What About Rainwater Catchment?” Hawaii County Department of Water Supply, accessed Oct. 13, 2023.

[4] Patricia Macomber, “Guidelines on Rainwater Catchment Systems for Hawai‘i,” College of Tropical Agriculture and Human Resources at the University of Hawaii at Manoa, 2010, p. 3.

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