HAWAI'I KAI — Hawai'i Kai-area residents next month will start paying for the second round of rate increases for sewer services implemented within the past two years.

Hawaii-American Water Co., the private sewer company that serves 11,000 East Honolulu residents, maintains that the higher fees are needed to upgrade its aging sewer system.

The state Public Utilities Commission last week approved the increases on an interim basis. Hawaii-American's September billing will reflect the new rates, said Lee Mansfield, the company's manager.

"We feel the new rate is fair for us," Mansfield said. "It's been a give-and-take negotiation."

Hawaii-American customers pay a flat fee for sewer service. Billings for O'ahu residents receiving city sewer service are based on water usage.

Monthly sewer service for single-family residences will now cost $54.55 — a 10.78 percent increase over the previous rate. Customers in multi-family residences, such as condominiums, will pay $45.75 a month — a 14 percent increase.

Last August, Hawaii-American had asked the PUC to approve higher monthly rates: $56.40 — a 12.49 percent increase for single-family residences, and $47.38 — a 19.1 percent hike for multi-family residences.

A typical single-family O'ahu household served by the city's water and sewer system pays $47.13 in monthly sewer fees.

"I don't mind paying more as long as the company is taking the money and using it to ensure that our sewer system is safe," said Hawai'i Kai resident Murray Luther.

Likewise, Hawai'i Kai resident John Steinmiller said he will gladly pay the higher rate if the money is used to keep the sewer system in good working order and prevents spills, such as the one that occurred into the Ala Wai Canal. In March, a pressurized main sewer line in Waikiki ruptured, and city officials responded by pumping 48 million gallons of raw sewage into the canal rather than risking backup into homes, hotels and businesses.

"When I flush that toilet, I want to make sure that everything goes as planned," Steinmiller said. "I don't want to see any more sewage spills."

The company will use the rate hikes to help pay for improvements to the community's sewer system, which includes many pipes that are more than 40 years old and in need of replacement. Hawaii-American is now relining corroded and collapsing pipes along Lunalilo Home Road.

The PUC's interim decision means that rates could be adjusted after two issues are resolved.

One pertains to whether an agreement made in 1961 that gives free sewer service to seven area parks, four schools, a fire station, a public library and Lunalilo Home is valid. Hawaii-American wants the PUC to end that agreement and direct the city and state to pay sewer fees.

The PUC also has to settle on a rate that Hawaii-American can charge the city for providing sewer service for homes on Portlock Road, in Kuli'ou'ou and the Paiko area.

How the issues are settled will determine whether the PUC considers further raising or lowering rates, said Dean Nishina, an analyst at the state's Consumer Advocate's Office.

Reach Suzanne Roig at sroig@honoluluadvertiser.com.