Hawaii-American Water Co. has notified state regulators that it plans to seek a rate increase early next year for sewer services it provides to about 30,000 homes in Hawaii Kai and part of Kuliouou.

The company said it has not yet determined the size of the increase, which will be announced when it formally files the request with the Public Utilities Commission.

Hawaii-American Water, a subsidiary of New Jersey-based American Water, said the rate hike is needed to cover rising expenses. The company began work in September on a project to replace a quarter mile of pressurized pipeline along Kalanianaole Highway and part of Lunalilo Home Road

Hawaii-American Water’s most recent rate increase was an average 8.4 percent interim increase granted by the PUC in October 2008. That decision, which boosted the monthly sewer fee to $58.70 from $54.55 for single-family homes, has yet to receive final approval from the PUC.