San Francisco supervisors voted unanimously Tuesday, Oct. 6, to impose an immediate, 45-day pause on approving permits for new data centers and expansions of existing facilities. The emergency ordinance makes San Francisco the first county in the Bay Area to adopt a temporary moratorium, while city officials consider longer-term rules for the facilities. District 10 Supervisor Shamann Walton proposed the measure, citing concerns about data centers’ energy and water use, air quality, noise, land use and effects on nearby communities. The facilities house computing equipment and supporting power and cooling systems; the growing demands of artificial intelligence applications can require more equipment and electricity, as well as water to cool servers. Walton said the pause would give the city time to assess those impacts and develop stronger protections and meaningful opportunities for public input. He also said San Francisco lacks a clear, comprehensive definition of data centers, making it difficult to determine how many operate in the city. The Planning Department currently groups them under the category “internet service exchange.” At a Monday meeting of the Board’s Land Use and Transportation Committee, more than a dozen people spoke in favor of the moratorium. Walton pointed to a data center approved on Paul Avenue in his district in 2016, saying the decision came without community input or transparency and under planning conditions that need updating. He said existing facilities are concentrated in Bayview-Hunters Point and the South of Market neighborhood, areas that have historically borne a disproportionate share of the city’s industrial pollution. Concerns raised in support of the pause have included potential effects on water supplies and noise near residential neighborhoods; the moratorium is intended to allow officials to examine those issues. The ordinance defines a data center as a facility housing computing infrastructure and associated power and cooling systems primarily used to process, store or distribute electronic data. That definition tracks language used by U.S. Sen. Alex Padilla in proposed federal legislation. An amendment from Supervisor Matt Dorsey clarifies that the pause does not cover businesses’ server rooms used for their own operations, rather than facilities serving customers’ off-site data needs. The temporary measure does not itself establish permanent regulations; supervisors are using the 45-day period to work toward longer-term city rules.