There are 600 cesspools on properties close to the Kahaluu Lagoon and the stream that feeds into it. The average cesspool holds about 3000 gallons of water and discharges about a thousand gallons of wastewater a day.
"It is supposed to actually leach through the ground. That's how it works. But when they fail they tend to come through the cap and just flow out," said Eddie Gonzales of Gecko Enterprises.
The Department of Health said some of the cesspools near the lagoon may be contaminating it with extraordinarily high levels of harmful bacteria. Gecko Enterprises services cesspool and septic tank systems.
"I know if they're near the shore it's a very swampy area so they're probably in the groundwater," Sam Gonzales said.
"The cesspools have been there for 30 years," said Eddie Gonzales. "It doesn't seem that all of them can be bad. But sometimes when it rains the ground gets saturated, then they won't flow as well."
Gonzales said if a cesspool is suspected of sending human sewage into the lagoon, dye can be put into the wastewater to see if it ends up there.
"I've seen it done in toilets to detect leaks," he said.
The Health Department's Gary Gill said other means to investigate could be monitoring groundwater and even going door-to-door to inspect cesspools. The bacteria count was highest where the stream feeds into the lagoon.
"It's surprising. I don't know if it's a spike or they haven't been testing over the years. I would be nervous if I was a homeowner around that area and they find a neglected cesspool," Sam Gonzales said.
It's also possible a resident with a cesspool in Kahaluu doesn't know they have a cesspool.
"Sometimes it's difficult. The system was put in a long time ago. People sometimes don't even know it's there," Eddie Gonzales said.
Watson Okubo of the Health Department's Clean Water Branch said hundreds of gallons of lagoon and stream water will have to be filtered to pinpoint the bacteria release hot spots. The high volume may make it necessary to filter the water and test it in the field instead of the laboratory. Another round of water sampling will be done Wednesday.