During heavy rain, many Hawaii residents think nervously back to the weeks of unremitting storms in 2006, when a broken sewer pipe released 48 million gallons of raw sewage into the Ala Wai Canal and beaches around the island were closed.

After falling into Ala Wai Yacht Harbor, a man died of organ failure due to massive bacterial infections.

The spill gave rise to a federal and state lawsuit against the City and County of Honolulu that was settled in a 2010 consent decree that compelled the city to pay a fine of $1.6 million and repair and improve its antiquated sewage system.

After eight years of work and regular reporting to the U.S. Environmental Protection Agency, the city has met the requirement of rehabilitating its 2,100 miles of sanitary sewer pipes, said Lori M.K. Kahikina, director of the Department of Environmental Services.

Kahikina said many people are unaware the sanitary and stormwater sewers are completely separate, but stormwaters can invade sanitary systems. For example, “several of our manholes are in Kalihi Stream, and when stormwaters rose high enough, the manhole covers could lift off.”

Since the consent decree, the department has installed locking manhole covers in the stream.

Asked whether she was happy with their progress, “I’m happy our spills have reduced drastically, but there’s always room for improvement,” Kahikina said. “In 2006 we had 200 sewage spills. Last year we had 44.”

While storms continue to provoke occasional discharges of more than 30,000 gallons of raw sewage into streams and the ocean, “to put it in perspective, Sand Island treats 67 million gallons of sewage per day, and in a major storm, that goes up to 250 million gallons a day.”

The next step under the consent decree is to upgrade the Honouliuli sewage plant from primary to full secondary treatment by 2024, and the Sand Island plant by 2035.

Meanwhile cesspools are stagnating, with no action yet being taken to replace any of the 88,000 cesspools in the state, as required by Act 125, passed by the Legislature in 2017, to happen by 2050.

A cesspool working group with representatives from the state, city and other stakeholders meets regularly to try and find solutions, particularly with regard to financing expanded sewer systems, said Sina Pruder, chief of the state Department of Health’s Wastewater Branch.

“If you see green algae in the ocean, it’s very likely it’s from cesspools’ effluent leaking into water,” said Health Department Director Bruce Anderson, noting that when it rains hard, cesspools flood, posing a health risk.

“Replacing cesspools with septic tanks is not really getting much improvement. The only solution is to sewer an area,” he said.

However, Anderson and Pruder said not all high counts of enterococci in beachwaters necessarily come from sewage.

On June 5 the Department of Health released a study of Kauai’s Mahaulepu and Waikomo watersheds showing that neither human nor animal waste was the source of bacteria in beach waters in those cases. DOH contracted the study by the Lawrence Berkeley National Laboratory, which used a new microbial source tracking tool called PhyloChip.

A news release on the study said the enterococci and other bacterial indicators are naturally found in Hawaii’s tropical soil.