Where every number in a report comes from
This tool reads published State of Hawaii GIS services. Nothing here is proprietary and nothing is modeled or estimated. The table lists every layer the product touches, so you can go to the source yourself.
Base URL: geodata.hawaii.gov/arcgis/rest/services
| What it is used for | Service and layer | Publisher | Refresh cadence |
|---|---|---|---|
| Finding your parcel and its Tax Map Key, statewide | ParcelsZoning/25 | State Office of Planning and Sustainable Development | Periodic, published by the state without a fixed schedule |
| Acreage and county assessment values, including the improved versus unimproved test | ParcelsZoning/5 Hawaii ParcelsZoning/9 Kauai ParcelsZoning/30 Maui | County real property tax offices, republished by the state | Annually, following each county assessment cycle |
| Wastewater system of record, by island | Infrastructure/22 to 26 | Department of Health, Wastewater Branch | Periodic. No layer exists for Lanai, so no wastewater record can be returned there. |
| Recorded cesspool points, proximity distances, sea level rise flags, soil suitability | Infrastructure/32 | Hawaii Cesspool Prioritization Tool, developed by the University of Hawaii Water Resources Research Center and Hawaii Sea Grant with the Department of Health, published by the Statewide GIS Program | Location data dates to 2008 for Oahu and 2010 for the neighbor islands, updated with permit records through 2020. Built from the Department of Health inventory. |
| Block conversion priority category and rank | Infrastructure/33 | Hawaii Cesspool Prioritization Tool, as above | Tied to the prioritization study, not on a schedule |
| County zoning district | ParcelsZoning/2, 3, 29, 33 | County planning departments, republished by the state | As each county amends its zoning maps |
| State land use district | ParcelsZoning/20 | State Land Use Commission | As the Commission acts on boundary amendments |
| Special Management Area boundary | ParcelsZoning/21 | County planning departments, republished by the state | Infrequently |
| FEMA flood zone | Hazards/6 | FEMA, republished by the state | As FEMA issues revised flood insurance rate maps |
| Lava flow hazard zone | Hazards/3 | United States Geological Survey | Rarely. The nine-zone map has been stable for decades. |
| Tsunami evacuation zone | Hazards/11 | Hawaii Emergency Management Agency | As the agency revises evacuation mapping |
| Geologic unit and age, dune and karst flags | Terrestrial/28 | United States Geological Survey | Rarely |
The Hawaii Cesspool Prioritization Tool releases its content and results to the public domain with credit to its authors. Credit: Hawaii Cesspool Prioritization Tool (HCPT), 2022 dataset, developed by the University of Hawaii Water Resources Research Center and Hawaii Sea Grant College Program in collaboration with the Hawaii Department of Health; published by the Hawaii Statewide GIS Program, November 2025. Tool credits: Christopher Shuler, Michael Mezzacapo, and Alyssia Renteria. No endorsement by the University, the Department of Health, or the State is implied.
How the snapshot works
A scheduled job copies these layers to a local store. Your lookup reads that copy, never a live request to the state. This keeps results fast and reproducible, and it means every report prints the date its snapshot was pulled. Two reports run on different days can differ, and the snapshot date is how you tell.
What the records do not contain
Systems that were never recorded by the state. Conversions completed after the permit records the cesspool inventory was last updated with, which run through 2020. Lava tubes, caves, and burial sites, none of which can be screened remotely. Sewer mains outside Oahu. County permit history outside Oahu.
There is no wastewater inventory of any kind for Lanai, Niihau, or Kahoolawe. A lookup on those islands returns parcel and hazard information with the wastewater section stating that gap.
Coverage by island
Share of parcels with any wastewater record at all. Where a parcel falls outside that share, the report says so and explains that no record is not the same as no system.
| Kauai | 52% |
| Hawaii Island | 40% |
| Molokai | 31% |
| Maui | 29% |
| Oahu | 8% |