San Francisco Supervisor Mark Farrell today called for the development of a citywide municipal fiber network that could deliver high-speed internet service to every resident in the city.

The ambitious proposal is intended to help bridge the digital divide, bringing Internet service to the more than 100,000 San Francisco residents who currently lack access, including 14 percent of public school students.

Farrell said the Internet “is no longer a luxury, it’s an absolute necessity” and should be widely available like other public utilities.

“When you turn on the faucet, clean water comes out. When you turn on the light switch, the lights come on,” Farrell said. “And when you open your laptop, everyone should have access to a fast Internet connection — whether you live in Pacific Heights or the Bayview.”

A budget and analyst report released today analyzed the likely costs and obstacles to providing such a network and the best models for the city to pursue.

Construction costs for a “utility-based” system connecting to every home like the one Farrell is championing could reach $867.3 million or more, with ongoing annual costs of $231.7 million, the report found.

The report recommended that the city reduce those costs by partnering with a private company and by imposing a monthly utility fee on residents and businesses.

Farrell also announced the formation of a Municipal Fiber Advisory Panel, co-chaired by Miguel Gamino, head of the city’s Department of Technology, and Jay Nath, head of the mayor’s Office of Civic Innovation.

The panel, intended to advise policy makers on expansion of the city’s fiber network, will begin meeting in April.

Sara Gaiser, Bay City News