HAWAI'I KAI — The private company that provides sewer service to Hawai'i Kai and part of Kuli'ou'ou is asking for its second rate increase in two years.

If the rate increase requested by Hawai'i American Water Co. is approved by the state Public Utilities Commission, the sewer bill for residents in a single-family home would jump 12.5 percent to $56.40 a month. Condominium homeowners would see an 18.1 percent increase, to $47.38 a month.

By comparison, the typical single-family O'ahu household served by the municipal water and sewer system pays $42.85 a month in sewer fees.

More than 10,000 East Honolulu residents found their sewer rates raised by 3.3 percent under new rates approved by the state Public Utilities Commission in 2003.

The company says the latest proposed rate increase — which would boost revenues 16.6 percent — is necessary to continue improvement projects that include manhole replacement and relining of aging sewer pipes.

A public hearing will be held on Oct. 27 to learn what residents have to say about the rate increases. Officials from the state Division of Consumer Advocacy will be at that meeting to hear community comments before making a recommendation on the new rates, said John Cole, executive director of the office.

"They're doing another rate increase?" said Bob Fowler, a Hawai'i Kai resident who lives in a condominium. "Didn't they just get one? It's an exorbitant amount they're asking for."

The last time around, the company wanted to raise monthly sewer rates by about 18 percent — $9 a month increase for single-family-home customers and a $7 a month increase for condominium customers — but the commission approved a smaller rate increase after hearing public testimony and a recommendation from the state's consumer advocacy division to not raise rates but to lower them. Before the 2003 rate increase, sewer fees were last raised in 1996.

Lee Mansfield, Hawai'i American Water manager, said the new rates are needed to continue upgrading the 40-year-old sewer system. The company is in the process of repairing sewer lines under parts of Hawai'i Kai Drive and along Lunalilo Home Road.

Sewer fees in East Honolulu do not include water charges, which come in a separate bill from the Honolulu Board of Water Supply. The city, which operates sewer systems for most of O'ahu, recently increased its rates. The City Council raised rates about 25 percent for 2006 and 10 percent over fiscal years 2007 to 2011.

Hawai'i Kai residents pay a flat sewer fee. The city charges a base fee plus a fee based on the amount of water used.

Hawai'i Kai resident Murray Luther said he couldn't understand the company's justification for a rate increase when so many new homes were hooking up to the company's sewer services.

"That's extra revenue from all those homes," Luther said. "Why can't the company use that money to fund its improvements?"

Reach Suzanne Roig at sroig@honoluluadvertiser.com.