William R. Sewell, former owner of several Hawai'i construction, home-inspection and real estate companies and a noted spokesman for the building industry, died yesterday in California. He was 80.

Sewell left Hawai'i 10 years ago and was living in Danville, Calif. He died at John Muir Hospital in Walnut Creek.

He first came to the Islands after graduating from the University of California-Los Angeles in 1950 to work for Matson Lines, ultimately serving as chief purser.

But in the boom years of the 1960s and '70s, he gained prominence in real estate. He was a principal and owner of numerous development and real estate companies: Waialae Builders Inc., Sewell Associates, Blue Moon Builders, Home Inspections Inc. and others.

While heading the Home Builders Association of Hawaii, Sewell was part of the debate over land issues such as private developers' role in providing park lands and other public improvements.

And that period also coincided with increasing activism in historic preservation: One of his residential projects in Nu'uanu drew attention from those worried about disrupting a possible archaeological site.

Among his many projects was the construction of custom homes as part of Tom Gentry's Waialae Iki development.

He was active with numerous civic organizations, including the Building Industry Association, the Sand Island Treatment Center and the Ala Moana Rotary Club.

Funeral arrangements are pending, but donations in his memory may be made to: Rotary Foundation, c/o P.O. Box 17040, Honolulu, HI 96817; or the Kline Welsh Behavioral Health Foundation, P.O. Box 3045, Honolulu, HI 96802.

He is survived by his wife, Bettye; sister Mary Frances Alexander of Sun City West, Ariz.; daughter Michele Harris of Kane'ohe; sons William S. of Halifax, Nova Scotia, and Scott R. of San Jacinto, Calif.; and three granddaughters.