Hawaiʻi has ordered every cesspool in the state closed or converted by 2050, and in July 2026 the governor signed a bill creating a revolving loan fund to help pay for it. What has been missing from that conversation is a clear picture of who actually owns Oʻahu’s cesspools — and how close they sit to the water. So we built one.
Oʻahu’s Cesspools in 2026: Who Owns Them, and How Close They Sit to the Water
We matched 6,763 Oʻahu cesspool parcels from the state’s Cesspool Prioritization Tool to current owner records in the City & County of Honolulu’s parcel database (343 parcels could not be matched to a verifiable owner and are excluded). Every figure below comes from that dataset. Last updated August 2026.
The headline numbers
Six numbers describe the problem better than any summary we could write:
- Cesspool parcels with a confirmed ownerOʻahu, matched to county records6,763
- Not occupied by their owner2,534 absentee in-state + 480 out-of-state44.6%
- Owned from outside Hawaiʻiacross 40 states — California alone holds 242480
- Within 100 meters of the oceanabout one football field1 in 6
- Within 1 km of a drinking-water well995
- Inside the DOH 2017 priority areasthe parcels the state flagged first2,798
Who owns them
The picture most people carry — a kamaʻāina family on the property their cesspool serves — covers barely half of them. 3,749 parcels (55.4%) are owner-occupied. The other 3,014 are not: 2,534 belong to owners at a different Hawaiʻi address, and 480 belong to owners on the mainland or overseas. California leads with 242 parcels, followed by Washington (38), Nevada (36), Texas (23) and Utah (21).
Ownership is also more concentrated than you would guess: 137 owners hold two or more cesspool parcels each — 331 parcels between them — and the largest single holding is 18. For those owners the 2050 mandate is not a home-repair question; it is a portfolio problem.
Where they are
By tax-map district, with the share not occupied by their owner:
- KoʻolauloaHauʻula, Lāʻie, Kahuku side — 58% absentee1,489
- KoʻolaupokoKāneʻohe, Kailua, Waimānalo — 38% absentee1,345
- WaialuaHaleʻiwa and the North Shore — 51% absentee1,240
- ʻEwaʻEwa Beach, Kapolei side — 22% absentee1,093
- Honoluluurban district — 42% absentee800
- Waiʻanae53% absentee767
- Wahiawā59% absentee29
The rural windward coast — Koʻolauloa and Waialua — carries the heaviest load and the highest absentee share. The districts with the most cesspools are precisely the ones where the owner is least likely to be living over them.
How close to the water
The reason the state cares is groundwater and nearshore water, so we measured every parcel’s distance to both. 1,075 parcels (15.9%) sit within 100 meters of the coastline. Widen to 200 meters and it is 1,861 (27.5%); within 500 meters, 2,867 — 42.4% of the parcels in this dataset.
995 parcels sit within a kilometer of a drinking-water well, and 2,798 fall inside the priority areas the Department of Health flagged in its 2017 report to the legislature. Under the state’s prioritization scoring, 1,340 of the 6,763 rank in the highest-priority tier.
What happens between now and 2050
Act 125 (2017) prohibits new cesspools and requires every existing one to be converted, connected to sewer, or closed by January 1, 2050. It applies to every cesspool in the state, not only those near the shoreline — we cover the common misreading of that separately. In July 2026 the state added the missing financial piece: a Cesspool Conversion Revolving Loan Fund, administered by the Hawaiʻi Green Infrastructure Authority, offering low-interest and forgivable loans. A conversion on Oʻahu typically runs $25,000 to $50,000 depending on ground conditions and access.
If you own one of these parcels, our Hawaii Cesspool Conversion Guide walks through the deadline, the costs line by line, and the help available right now.
Why this counts 6,763 where the state counts more than 11,000
Both figures are right — they count different things. The Hawaiʻi Department of Health estimates more than 11,000 cesspools on Oʻahu, a figure from its 2017 report to the legislature. This dataset counts 7,106 Oʻahu parcels that the Cesspool Prioritization Tool actually maps, 6,763 of which we could match to a current owner.
Three things account for the gap. A parcel is not a cesspool: one parcel can hold more than one system, and the tool maps parcels rather than individual cesspools. The tool contains the cesspools the state has been able to locate, which is fewer than it believes exist. And the DOH figure is an estimate drawn from an assessment now close to a decade old.
So treat 6,763 as a floor with names attached to it rather than a census. It is the number of Oʻahu cesspool parcels whose ownership can be verified in county records today — which is what makes the ownership and proximity breakdowns above possible at all.
Using this data
Journalists, researchers and policymakers are welcome to cite these figures with attribution to Golden Penny Sanitation Inc. We can cut the dataset by district, priority tier, or ownership type on request — email goldenpenny808@yahoo.com or call (808) 630-9966.
Method notes: parcel list from the University of Hawaiʻi / DOH Cesspool Prioritization Tool; ownership from City & County of Honolulu real property records (August 2026); “absentee” means the owner’s mailing address differs from the parcel address; distances computed from parcel geometry. Figures describe parcels we could match to a current owner and are a floor, not a census — the University of Hawaiʻi Sea Grant Cesspool Prioritization Tool, the source of this parcel list, puts the statewide total above 83,000, and the Department of Health estimates roughly 88,000.