Short answer: yes. Under State law, every cesspool in Hawaiʻi has to be upgraded, converted, or connected to a sewer before January 1, 2050. That includes the one under your yard, even if it has never given you a day of trouble.
It is a reasonable thing to doubt. A cesspool is out of sight, and if the toilets flush, it feels like it works. So it helps to know what it is actually doing down there.
A hole in the ground, and where its contents go
A cesspool is a hole in the ground. What goes down your drains goes in, and the liquid soaks out through the bottom and sides with almost no treatment. A septic system, by contrast, has a tank that separates solids and a field that lets treated water spread out slowly. A cesspool skips all of that.
On much of Hawaiʻi Island the ground under that hole is young, cracked lava rock, and water moves through it quickly. Nobody has to guess how quickly, because University of Hawaiʻi researchers have measured it.
- Toilet
- Cesspool
- Lava rock
- Groundwater
- Ocean
At Puakō, UH Hilo scientists put dye into home wastewater systems and watched for it along the shore. It came out of shoreline springs in as little as 6 hours, and the slowest took 10 days. In front of 81% of the homes they sampled, bacteria broke the State’s swimming standard.
Puakō is not a one-off. In Keaukaha, near Hilo, a 2025 UH Hilo study traced sewage into coastal waters and reefs, with dye reaching the shore in 20 hours to three days. And in Kona, researchers found sewage leaking into Kahaluʻu Beach Park from homes near Aliʻi Drive.
How big is the problem here?
Statewide there are about 83,000 cesspools. About 48,600 of them are on Hawaiʻi Island, which is more than half. According to the State’s Cesspool Conversion Working Group, together they put about 29 million gallons of untreated wastewater into the ground on this island every day.
- cesspools on Hawaiʻi Island, more than half of the State’s (Working Group, DOH, 2022)
- about 48,600
- cesspools on Hawaiʻi Island, more than half of the State’s (Working Group, DOH, 2022)
- gallons of untreated wastewater a day from those cesspools (same report)
- 29 million
- gallons of untreated wastewater a day from those cesspools (same report)
- the deadline for every cesspool (HRS §342D-72)
- 2050
- the deadline for every cesspool (HRS §342D-72)
The concern is highest in Puna, where roughly 9,300 cesspools sit in a narrow corridor on Kīlauea’s east slope, about 17% of all the cesspools in Hawaiʻi. Much of Puna has no public water, so families depend on wells and rain catchment. When the Department of Health sampled domestic wells there, it found wastewater bacteria in about a quarter of them. Puna, Hilo and Kona hold the State’s highest-risk areas.
Why a deadline, and why 2050
Hawaiʻi banned new cesspools in 2016. A year later, Act 125 (2017) required the existing ones to go as well. The deadline written into HRS §342D-72 is 2050, and it is the same for everyone, whatever priority area your home falls in. (Earlier deadlines for priority areas have been proposed but not passed.)
The law does let the Department of Health exempt a cesspool when conversion is truly not feasible, for example on some very small lots. Lot size and conversion explains how that works. Nothing requires you to convert when you sell, but that does not change the deadline. It only means the bill can land on whoever owns the home later.
Out of sight is not out of the water.
What it costs, and who you call first
Hawaiʻi County’s 2025 task force put the median conversion on this island at about $40,000, with an upper range near $70,000. On top of the price, most families face a stack of unfamiliar steps: an engineer, State approval, a contractor, inspections, and a way to pay. Who do you even call first? What the cesspool law means for your wallet and your home’s value goes through the money in detail.
That is the part ʻĀina Force exists for. We don’t dig, design or permit anything. We review your property, point you toward funding, and stay your one point of contact while licensed, independent engineers and contractors do the work under their own agreements with you.
If you want to know where your own yard stands, the free property check shows your parcel and its State priority area in about a minute. You can also call 808-ONE-WAVE.
