Civil libertarians are worried about an increasingly common form of domestic surveillance that has nothing to do with listening to your phone calls or reading your emails; it has to do with looking through your garbage.

Municipalities across the United States are implementing intrusive methods of monitoring the stuff people throw away as part of a push to increase efficiency and conformity to recycling rules. But the end result is that some garbage trucks now have the ability to record the contents of your trash cans on video to inspect each object.

“This kind of automated garbage monitoring raises very serious privacy concerns,” the American Civil Liberties Union warned in a press release on Friday. “While encouraging residents to recycle is commendable, any program involving the government’s systematic monitoring of citizens crosses a line. The contents of your trash can be surprisingly revealing.”

Residents in several Wisconsin cities are already subject to the new video monitoring practice. In Seattle, where garbage men can visually inspect garbage and levy fines on bad recyclers, residents are suing the city for violating their privacy.

There are also digital methods of tracking people’s garbage. In some cities, trash cans are monitored with RFID devices (Radio-Frequency Identification); the chips are attached to the bins, so that computers inside trash trucks can determine and record their movements. In Charlotte, N. C., collectors monitor the chips to “track and manage cart inventory,” and determine who is actually putting their recycling bin out on the curb. Dayton, Ohio, has been tracking trash can locations since 2010, and residents who recycle are eligible for a cash prize. In Cleveland, if the chip shows a recyclable cart hasn’t been brought to the curb in weeks, a trash supervisor can sort through the trash and impose a $100 fine if the regular trash has more than 10 percent recyclable material — although no fines have yet been levvied.

Police have used trash to gather evidence on suspects for years. In a 2010 issue of Police Chief, a trade magazine for law enforcement, one article urges officers to use trash cans that are “moved from a house and to the street for disposal” as “fair game for anyone — even the police — to take it away for inspection.” The authors of the article suggest that people very often leave behind incriminating evidence in their trash unsuspectingly, and have no reasonable expectation of privacy once the trash hits the curb.

If law enforcement officers could access the garbage truck cameras, they would not even have to visit the property and seize the trash.

According to Sonia Roubini, who researched the trash surveillance programs for the ACLU by compiling news articles about the programs, most cities contract with large companies to acquire bins, garbage trucks, and sometimes the cameras or RFID chips. She said she was surprised at how few reports about the programs expressed any sort of concern for privacy. “Most of the reporting that I found on RFID usage in trash collection were either praising programs for their innovative approach to encouraging recycling, or very briefly alluding to the potential privacy implications,” she wrote in an email.

According to a study ordered by a European Commission in 2012, the “barriers” to using RFID chips include the “need for a regulatory framework regarding security and privacy issues.” The authors cautioned that people might even stop using legitimate waste services because of privacy concerns, or an unwillingness to pay fines.

But in the U.S., it’s full steam ahead on trash surveillance. “It’s very crazy,” says Roubini. “Also not entirely surprising given the prevalence of surveillance technologies. Nothing is safe, not even our trash.”