Hawaiʻi County ‘behind the 8-ball’ to meet required conversion of 48,000 cesspools

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In 2017, the the State Legislature passed Act 125, requiring all cesspools be converted to more environmentally friendly systems by 2050. But more than five years later, Hawai’i County still has all of its 48,596 cesspools to convert.

“We haven’t even started,” Ramzi I. Mansour, director of the county’s Department of Environmental Management, told Hawaiʻi County Council members during a committee meeting Tuesday. “We’re already behind the 8-ball.”

The problem is exacerbated by a state funding gap of about $1.1 billion for the conversion of all of Hawaiʻiʻs approximately 83,000 cesspools, which discharge an estimated 50 million gallons of raw sewage into the groundwater and surface waters every day. This also presents a risk of human illness and harm to streams and coastal resources, including coral reefs.

Mansour, along with Cari Ishida with Carollo Engineers and Sina Pruder with the Department of Health’s Wastewater Branch, presented the study conducted by the Cesspool Conversion Working Group to the county’s Communications, Reports, and Council Oversight Committee.

Cesspools may be upgraded by connecting to a central or localized sewer system, or
installing an individual wastewater system on-site.

The working group has advised moving up the deadline for converting the worst offenders by 20 years, to 2030.


The group ranked the cesspools. Priority Level 1 cesspools had the greatest contamination hazard, followed by Priority Level 2 (significant contamination hazard) and Priority Level 3 (pronounced contamination hazard).

To see where the cesspools are located and their ranking, click here. For the Hawaiʻi Cesspool Prioritization Tool, click here. You can scroll on the site to find all the islands.

Hawai’i Island has the most priority 1 cesspools (5,119 or 37%) — primarily to the west of Waimea and around the Kona area — that would require conversion by 2030, if the proposal is passed.

“You’re looking at 713 conversions per year [of the priority 1 cesspools] and we have to start tomorrow,” Mansour said.

Hawai’i County has the biggest challenge in the state. For starters, it has 34,000 more cesspools to convert than the county with the next biggest number of cesspools (Kaua’i with 14,300).


Hawaiʻi County residents also have the least access to centralized sewers in the state at 71%, according to the working group’s study.

And, to make matters worse, the report found that Hawaiʻi Island homeowners also will be the most financially affected in the state. On average, cesspool upgrades would exceed 2% of a Hawaiʻi County residentʻs income after a potential $10,000 rebate that the state could secure through grants and other means.

According to the study, the cesspool conversion construction cost could range from $10,000 to $38,000. While the most common conversion is a septic tank to connect to an existing or new public sewer, working group members said there needs to be a variety of sewage conversion and funding options.

In 2018, to address the significant challenges raised by this conversion requirement, Act 132 established the Cesspool Conversion Working Group, tasked with further studying this issue and developing a long-range, comprehensive plan for the conversion of all cesspools in the next three decades.

Mansour told the County Council on Tuesday that the county has started consultant work for its wastewater integrated management plan in the Puna District and Pāhoa area. The same consultant is putting together a master plan to figure out how to serve the Puako and North Kohala areas.


Additionally, Mansour said phase one of the Hilo Waste Treatment facility plan is out to bid. The $100 million project is set to be complete in less than a year. The county is getting phase two of the project out to bid next year.

Council member Holeka Inaba, who represents North Kona to parts of Waikōloa, was curious to know how all these plans relate to one integrated wastewater plan.

“We’re seeing piecemeal plans but not one where it’s all coming together as a cohesive plan for the county and I feel we’re banging our heads here because we don’t have that comprehensive plan,” Inaba said.

Mansour said funding was a major factor into why they are proceeding with one plan at a time.

“The county can’t afford that much money all at once,” he said. “So each district or area was granted a certain amount of money and they’re utilizing those funds to address the cesspools in pieces.”

Eventually, once all these pieces are put together, Mansour said the county will hire a consultant to bring those plans together into one major integrated plan.

The 2022 report of the working group is available here.

Tiffany DeMasters
Tiffany DeMasters is a full-time reporter for Pacific Media Group. Tiffany worked as the cops and courts reporter for West Hawaii Today from 2017 to 2019. She also contributed stories to Ke Ola Magazine and Honolulu Civil Beat.

Tiffany can be reached at [email protected].
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