Effective Nov. 1, the Multnomah County Library, the nation's second-busiest for its size, is updating its rules for the first time in 20 years.

The 27 rules now governing behavior suggest the library is struggling to deal with homeless patrons who spend much of the day in library buildings.

The most contentious areas: Food is now banned in most cases, drinks are limited to 24 ounces, and personal belongings cannot impede staff or patrons. And the library is cracking down on "lounging" and sleeping, as well as the use of restrooms for "bathing, shaving and washing hair."

Animals, service and otherwise, have also become contentious. Only recognized service animals—dogs, miniature horses or monkeys—are allowed.

Library spokesman Shawn Cunningham says the rule revisions were two years in the making, including extensive public input. "We want the library to be a welcoming environment for everyone," Cunningham says. "It's a balancing act."