Honolulu city officials could begin work as early as next month on a permanent fix to the Waikiki sewer line that ruptured March 24, but the $30 million initial price tag is likely to grow beyond $50 million over the next five years, they say.

City Environmental Services Director Eric Takamura said running a temporary bypass pipe through Waikiki will cost $8 million to $12 million. And fixing the old line will cost $10 million more, he said.

The line is a top priority after the break prompted the city to pump 48 million gallons of raw sewage into the Ala Wai Canal rather than risk sewage backing up into the homes, hotels and businesses nearby. That spill sent bacteria levels skyrocketing in nearby ocean waters, keeping swimmers away from some of Waikiki's famous beaches for days.

Yesterday, Takamura was still filling out the paperwork requesting "emergency procurement" that would allow the city to hire a contractor within weeks.

The $30 million in this year's budget will go to pay for construction of a new sewer line to replace the 42-inch pressurized force main that broke. Takamura said a flexible temporary line would allow sewage to be moved away from the area where the break occurred.

But he said neither the price nor the design is set.

And he said engineers haven't determined whether the temporary line should be one 42-inch pipe or two 24-inch pipes, which might be less obtrusive. He said the line tentatively would go under Kai'olu Street (where the break occurred), then along the Ala Wai Canal until it reaches Ala Moana Boulevard and goes into another line.

He said the pumps that were used to divert sewage into the canal during the break would be used to move sewage into the temporary line.

He said construction of a major sewer line through Waikiki would take years, and additional time could be needed to reinforce the old Beach Walk main so it could be used as a backup if another sewer line in the area broke.

Takamura said doing all that construction in the busy tourist hub could take time.

"That (temporary) line may be there five or six years," he said.

Reach Robbie Dingeman at rdingeman@honoluluadvertiser.com.