It’s hardly news that local TV newscasts are the most popular source of community information. Surveys and Niel­sen ratings have shown that for years.

But the second most widely followed source of local news isn’t the newspaper, radio or the Internet. It’s the oldest and most basic form of human communication: word of mouth.

The importance of neighbors, friends and co-workers as information transmitters is highlighted in a new study that suggests that the dinner table, the back fence and the water cooler make up the ultimate social network, over which some of the most important and relevant news is transmitted.

Word of mouth outranked every new and traditional form of news media except local TV news as the most frequently consulted news source in the study, released Monday by the Pew Research Center and the Knight Foundation. Their report suggests people get news about their communities through a complex “information ecology” that involves multiple sources and media, some mass and some interpersonal.

The role of human-to-human communication in news is both obvious — people have always told stories to one another — and revelatory, primarily because data and studies have long focused on the news media, not on all of the ways news actually gets around.

Local TV news still sits atop the information pyramid, according to the study, but its role is narrow and even fading. In a nationwide survey of 2,251 people, 74 percent said they turned to local TV news at least once a week to get information about their community, more than any other source.

Word of mouth ranked second (55 percent), followed by radio (51), newspapers (50) and the Internet (47). The latter category includes search engines, social networks such as Facebook, and blogs and Web sites not associated with a traditional media source such as a TV station or newspaper.

Marketers have always known that word-of-mouth advertising, or buzz, is critical to selling a product, but its role in news hasn’t been well studied.

The quality of word-of-mouth information, of course, varies considerably from the kind one gets via professional reporters (as the wildly inaccurate character who reports “Second-Hand News” on “Saturday Night Live” demonstrates).

On the other hand, interpersonal news usually comes from a known and trusted source, and helps people “triangulate” or vet information that may have been reported by the mass media, said Tom Rosenstiel, director of the Project for Excellence in Journalism, one of two Pew-funded organizations behind the research. It also may be far more specific and personal than anything the media can provide, he said, such as who’s the best fourth-grade teacher at the local school.

Local TV news ranked as the leading information source in the study primarily because it’s the go-to medium for the handful of subjects people said they followed most: weather, breaking news, politics and crime. Weather was, by far, the most widely followed among the 16 topics researchers asked about, with 89 percent of adults saying they keep up with weather news.

But TV ranks low as a source on many other topics, such as news about businesses, schools, government and cultural events. And its appeal is primarily to people over 40; younger people say they are increasingly getting their news from other sources, such as the Internet and mobile phones.

Newspapers, meanwhile, were the most widely cited source for a wide variety of topics, though the topics were generally of lesser interest. Newspapers (print and online) ranked first or tied for first in 11 of the 16 news categories that researchers asked about, such as government, cultural events, schools and housing (sports was not on the list because researchers determined the term implied too many variables, including professional, college, high school, youth and participant sports).

Despite this, the news for newspapers seems ominous. Some 69 percent of the people surveyed said that if their local paper no longer existed, it wouldn’t have a major impact on their ability to learn about news in their community.

Word-of-mouth information tends to fill in gaps in the media infrastructure. Its importance rises the less a subject is covered. A Brookings Institution study this year, for example, found that “family and friends” were the most popular and highly regarded providers of education news.

“People rely on people they know because there’s no other source for a lot of this information,” said Russ Whitehurst, a co-author of the Brookings report. The track record of a local school or teacher “isn’t in the newspaper or online.”

The poll in Pew’s study, “How People Learn About Their Local Community,” has a margin of error of plus or minus 2 percentage points.