Act 217 Sewer Expansion Overlay
Overview
The Act 217 Sewer Expansion Overlay identifies 103 Potential Project Areas across Hawaiʻi where connecting cesspools to a centralized sewer system may be technically and economically feasible. While the Hawaiʻi Cesspool Hazard Assessment & Prioritization Tool (HCPT) ranks individual cesspools based on environmental and public health risk, the Act 217 Sewer Expansion Overlay evaluates areas based on the relative feasibility and cost of sewer system expansion. The tool was developed by the University of Hawaiʻi Water Resources Research Center and UH Sea Grant College Program in support of Act 217 (2024).
Limitations
Resources
This is a planning-level tool, not an engineering study. It does not represent official county infrastructure plans, and inclusion of an area does not indicate county funding, approval, or prioritization. Sewer projects of this type typically require years of detailed engineering planning, geotechnical investigation, and environmental review, which is outside of the scope of this statewide screening analysis. The data used in this analysis reflects the best available information but may contain errors and should not be used for engineering or legal purposes. Data may be updated periodically. To report an error or submit updated information contact cshuler@hawaii.edu.
For More information about the tool please see the Final Project Report below.
To read Hawai’i Act 217, which enabled the creation of this tool, see the offical text below.
Explore Further
Cesspool Conversion Working Group
Report to the Legislature 2022 Regular Session
Act 125: Requires upgrade, conversion, or sewer connection of all cesspools before 2050
Hawaiʻi State Legislature
Contacts:
For more information on the HCPT and Act 217 Wastewater Overlay, contact 
Christopher Shuler, cshuler@hawaii.edu