WASHINGTON — Bonnie Klem has been walking into homes for more than 15 years, and the signs that something is wrong are often visible from the sidewalk: There’s an odor, or the blinds are always drawn. There are piles of rusted fenders on the lawn or several broken vacuum cleaners on the front steps. Sometimes the back-yard grass is barely visible through piles of stuffed plastic bags.

Inside, stacks of newspapers reach the ceiling. Toppled boxes, exploded cans of spaghetti sauce, office supplies and garbage block the hallways. The stairs are crumbling, and the floors sometimes give way to the weight of one person’s stuff.

These exceptionally cluttered homes fall into the category of hoarding, a problem that local, regional and national authorities consider a matter of public health and public safety. It is also now recognized as a significant mental health issue, one that experts say causes its sufferers to accumulate objects to the point that they become emotionally attached to and perhaps endangered by them.

Some local jurisdictions are setting up hoarding task forces to coordinate their responses and raise awareness of the issue. Simply hauling out the trash and encouraging the hoarder to start over with a clean house can be emotionally damaging and futile. Now, officials use resources across a broad spectrum to get hoarders the help and support they need.

“There is such a thin line between people saying, ‘Oh, those quirky slobs,’ and recognizing that this is a disease and that they need help,” said Klem, a member of the suburban Montgomery County (Md.) Hoarding Task Force. “These people are becoming victims of their things. We’re trying to get a better edge on how to help hoarders and to get people to understand the problem.”

Experts estimate that 2 percent to 5 percent of the population demonstrates some sort of hoarding behavior, meaning millions of Americans need help. Awareness has been bolstered by popular television shows depicting hoarders and those trying to intervene. But some warn that those cases spotlight only people willing to allow cameras into their home and don’t focus on the vast majority, who try to hide their condition and its evidence.

Gail Steketee, dean of Boston University’s School of Social Work, is a hoarding expert and co-author of “Stuff: Compulsive Hoarding and the Meaning of Things.” She said the problem can be compared to “a little bit of pack rat behavior gone haywire.”

“Many people like to save things,” Steketee said. “The trouble with hoarders is they like to save things and struggle hard emotionally with letting things go.  …  The objects become more important than being able to use the home. They’re so addicted to what they have that they can’t live without it.”

Taking it away can cause sufferers to grieve deeply, almost as if they’ve lost a loved one, and lead to depression.

Steketee said the task forces aim to deal with hoarding when it reaches the public sector, such as when a home filled with objects becomes unsafe for habitation or when piles of brittle papers are a fire hazard. Such homes can endanger neighbors, too.

“If the person is not willing to be helped, the task forces get together and consult with each other and figure out who can get a foot in the door in order to establish a relationship with this person,” Steketee said. “Someone with a serious hoarding problem usually has other social-service needs in addition to mental-health needs.”

Michael Congleton, chairman of the suburban Fairfax County (Va.) Hoarding Task Force, said cases often involve people who need help from several agencies. The fire department might discover a hazardous home with children, elderly adults and animals living inside. Suddenly, help is needed from adult protective services, animal control and child protective services.

“Members can come up with a plan saying we need to have a coordinated inspection and know what to expect,” Congleton said. The county sees 130 to 150 reported cases of hoarding each year. “It’s a great way to share information among the appropriate people so you don’t have four different agencies doing four different things.”

Klem said the problem can seem “illogical” to those who aren’t in the middle of it, because it would seem obvious simply to clean up the house and hope the hoarder then maintains it. But hoarders don’t understand they have a problem until they are forced to face it.

Task forces aim to help hoarders avoid eviction and public-safety threats and get treatment, Klem said. Authorities view hoarders not as troublemakers but rather people needing help.

“People are not trying to do something that is wrong,” Klem said. “To them, it’s right. It’s a mental illness, and we’re hoping to get that understood.”