As Hawaiʻi County nears the state deadline to eliminate cesspools, the price tag for conversions keeps climbing.
About 49,000 cesspools are scattered around Hawaiʻi Island. An analysis by the state Department of Health found that contamination from cesspools in Keaʻau, Hilo, and Kona may pose a risk to drinking water resources or nearshore coral reefs.
The state Department of Health has mandated that all cesspools be converted to compliant septic systems by 2050. In order to meet that mandate, Hawaiʻi County needs to convert roughly 2,000 cesspools a year.
But the cost of that work is “astronomical,” according to Chris Laude, the acting division chief for Hawaiʻi County Department of Environmental Management.
The department enlisted the environmental firm Carollo Engineers to assess conversion options for the county. According to the firm’s findings, the price tag to eliminate cesspools could range from $2 to $5 billion.
A higher-cost strategy involves hooking up more households to decentralized sewer systems and new treatment plants, whereas a more affordable route would be to convert each cesspool to an individual wastewater system.
But individual septic systems may not be the best solution for the environment in every location because they might not process wastewater as well as a sewer system.
"The cheapest way seems to be the most attractive. However … you may not get any treatment of the liquid train, so that the net impact on the nearshore waters is not going to be as dramatic of an improvement as you might hope,” Laude said.
