The city says it plans to repair five of the seven pressurized sewer mains tagged "very critical" by consultants in 2004 to try to prevent another rupture like the one that caused a record raw sewage spill last month in Waikiki.

But actual work may not begin for years.

The lines were described as old and corroded. If they break, raw sewage is likely to spill into storm drains that lead to nearby waterways and shores, city environmental services director Eric Takamura said.

He said some of the seven are less critical than others because major work on them was done more recently than on the 42-inch concrete pipe that broke on Kai'olu Street in Waikiki.

But Takamura views one of the lines — a 30-inch line in Waimalu — as a major risk because it hasn't had major work or inspection since 1964, the year it was laid and the Waikiki line was built. However, he noted, that line handles 7 million gallons a day, less than half that of the Waikiki line.

Money for work on some of the planned improvements has already been budgeted, but actual construction is likely years away. That's due in part to a budget process that generally takes nearly five years to get a project to the point of construction, according to Jack Pobuk, a city engineer who tracks wastewater construction spending.

Other factors include the sheer expense of sewer repairs and a slow-moving bureaucracy.

Attorney Lea Hong, who represents Hawai'i's Thousand Friends and other environmental groups that sued the city to improve the sewer system, said the Hannemann administration appears to be pushing hard to identify the right priorities.

But she believes solutions need to be speeded up, and that may take big changes, Hong said.

"One thought would be to pass legislative or City Council measures allowing the city to fast-track sewer repairs without having to get special management area permits or do environmental assessments," Hong said.

Mayor Mufi Hannemann said Friday that he was interested in hearing more about that idea.

Hong also called for an overall assessment of the sewer system.

"We want the city to do an evaluation of the system in a comprehensive way and determine which (pipes) are old, corroded and are near major waterways that would result in catastrophic health risks to the public," she said.

Attention has focused on these pressurized major sewer lines, known as force mains, after the one that broke in Waikiki on March 24 prompted the city to pump an estimated 48 million gallons of raw sewage into the Ala Wai Canal.

Hannemann said pumping into the canal that runs through the resort community was "the lesser of two evils" compared to the option of allowing sewage to back up into nearby homes and hotels.

Takamura said some spills — even from force mains — could be averted. If a spill occurred during dry weather, it would be easier to cope with, he said. If it was a pipe of 24 inches diameter — compared to the 42-inch main in Waikiki — "there's a lot of different options we can use," Takamura said.

Officials might be able to quickly put in a temporary bypass line that could run above-ground while repairs are made; they could use tanker trucks to pump down the levels; or they would re-route the wastewater. Or engineers can sometimes find a way to contain a spill, Takamura said.

Hong said force mains are critical because the volume of sewage going through a force main is much greater than other sewer pipes. That's because sewage is generally flowing from homes and businesses downhill via gravity to a level area, but force mains are pressurized to allow the city to move large amounts of sewage to wastewater treatment plants.

Takamura noted that the city has spent money replacing force mains at Ala Moana Boulevard and Hart Street near Kapalama Basin, two of the city's highest-flow sewer lines.

Many factors can bog down major sewer projects: the expense, the government budget process and public reluctance to deal with sewage up-close-and-personal in their neighborhoods. That's the assessment from engineers working to design solutions and community advocates who are pushing for improvements.

Kailua resident Donna Wong is executive director of Hawai'i's Thousand Friends, which has been pressuring the city for sewer improvements since the 1990s.

She said it can be easy to ignore the sewer system, both for residents — who don't want to pay higher sewer fees — and for politicians who know that construction sometimes disrupts and divides communities.

"It's not a sexy issue," Wong said. If there's a spill every now and then and not a lot of people are affected, people don't think about sewage and the consequence of not spending enough time and money on maintenance and improvements, she said.

"It's just the typical not-in-my-backyard syndrome," Wong said. "Nobody wants sewage treatment or pumping station or landfill next door to them."

But in her other community role — as a longtime member of the Kailua Neighborhood Board — Wong said residents who are informed early of the needs and problems tend to be more receptive.

Wong's environmental group tagged one of the "very critical" force mains — the one in Kailua Heights — as a problem in the 1990s. She said the city recently completed an environmental assessment for a new, bigger sewer line and the plan is moving forward and gaining community approval.

Pobuk, the city engineer, said the city has budgeted for some of the planned improvements to the seven critical sewer mains, including: