Early next year, diners in Boston will get a new tool to learn how clean a restaurant is — a city-issued letter grade rating the establishment's food safety practices.
For the first year of the new initiative, a letter grade — either an A, B, or C — would be posted online only. But if the rollout goes smoothly, the grades would be displayed in storefront windows of every restaurant in Boston, resembling the systems that New York, Los Angeles, and other cities have been using since as early as the late 1990s.
When a restaurant gets a low grade (C would be the lowest), inspectors would return within 30 days to reinspect, city officials said. If the violations are corrected, the city would bump up the grade accordingly. If the issues remain, the grade would stand until the next routine inspection.
"We want to make it as simple as we can for people to understand the health conditions at our restaurants," William Christopher, head of Boston's Inspectional Services Department, which will oversee the program, said Monday.
Ratings will be assigned to all of the city's roughly 3,000 food establishments, including restaurants, food trucks, cafeterias, and other food vendors.
in May, the Globe reported that city inspectors in 2014 had found serious health code violations at nearly half of Boston's food-service establishments and vendors.
Christopher said he went to New York City recently to review its program, which began in 2010. He also has researched grading systems in other cities, including Los Angeles, which has been issuing grades since 1997.
Locally, Newton launched a similar program last month that requires numerical ratings to be displayed inside restaurants.
Christopher noted that officials in other cities have said their grading systems reduced health violations, improved public awareness about food safety, and even boosted business for restaurants by increasing competition for owners to keep cleaner stores.
Restaurantgoers applauded the idea Monday.
"It's good to know what you're getting into before you walk in to eat," Allison Rennie, a 19-year-old from the North Shore and a freshman at Wheelock College, said while shopping at Downtown Crossing.
Bob Luz, president and chief executive of the Massachusetts Restaurant Association, reacted cautiously to Boston's initiative. He said that such systems can oversimplify the results of restaurant inspections, which he noted the City of Boston already makes available online in detail.
"Many of the regulations relative to food safety are not easily understood at first glance by the general public, and letter posting neither necessarily nor accurately reflects the food safety conditions in a food service establishment," Luz said in an e-mail Monday.
Christopher said he expects no additional cost to the city or to restaurateurs because of the letter-grading system.
Putting it in place will not require City Council approval, he said, but the Inspectional Services Department plans to present the plan to councilors as well as to leaders in the local restaurant industry before launching a pilot program around the beginning of the year.
Inspections are done at least once per year at each restaurant, though some are inspected more frequently if they primarily serve populations that are particularly vulnerable to food-borne illness, such as the elderly and young children.
A complaint about food safety would also prompt a city inspection.
The city began posting data about restaurant inspections online in 2007, shortly after a Globe investigation of inspection reports for 50 eateries in Boston revealed how city inspectors had found serious violations at nearly half of the locations, including high-end restaurants.
A recent Globe review of inspection data found that during 2014, at least two violations that can cause food-borne illness — the most serious type of infraction — were discovered at more than 1,350 of the 3,000-plus establishments in the city that serve food.
A violation is classified under the most serious category when inspectors observe improper practices or procedures that research has identified as the most prevalent factors in food-borne illnesses.
Examples of such infractions include not storing food or washing dishes at the proper temperatures, employees not following hand-washing and glove-wearing protocols, and evidence that insects or rodents have been near food.
Typically, food-borne illnesses cause minor symptoms — the Centers for Disease Control estimate that 1 in 6 Americans get sick from food each year — but they can be serious.
Nationwide, an estimated 128,000 people are hospitalized each year because of food-borne illnesses, and 3,000 die from them.
Devynn Michel, 25, of Randolph, who was on Boston Common mulling where to eat with friends Monday afternoon, said he supported the new rating system. But it should not be too strict, he said, particularly for restaurants that have developed good reputations over many years.
It would seem unfair, for example, if a location is "generally a very clean restaurant, but that one time they have something wrong, all of a sudden they get a bad grade and lose customers," he said.
"But if they're . . . awful all the time, they deserve the grade."