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7th Circuit Rules That Law Enforcement Needs a Warrant to Get Smart Electrical Meter Data

August 27, 2018

TechCrunch reported on August 22^nd that the 7^th Circuit had issued its ruling in Naperville Smart Meter Association v. Naperville requiring a warrant in order for law enforcement to access smart water meter data.

Let's walk back a few steps. Traditional spinning meters are read perhaps once a month by your local utility- that reading isn't going to tell you a whole lot. It might tell you that the house was had abnormally high electricity use – potentially useful information if you suspected a pot farm was in the basement.

Smart meters send exact meter readings at short intervals, as often as every 15 minutes, and these readings may be kept for years. With that much detail you could not only tell whether someone lives in a house, but whether they're home, what room they're in, how often they do laundry, and on and on.

That data is revealing enough that the court ruled that people with smart meters have a reasonable expectation of privacy and that law enforcement will require a warrant to acquire that data. What if law enforcement wants to prove that someone was at home at a certain time in a criminal investigation? Citizens in Naperville, Illinois were concerned about their constitutional rights.

So a group of those citizens sued the city, which mandated smart readers several years ago, alleging that collection of the data was unconstitutional as an unreasonable search.

An earlier court decision found that by voluntarily sharing electricity consumption data with a third party, residents surrendered their right to privacy. If they have no privacy rights, the court concluded that it was not a "search" to ask for the data.

But as the 7th Circuit pointed out, there isn't really isn't a third party: the city collects the data, and city authorities want to use the data. And even if there were a third party, "a home occupant does not assume the risk of near constant monitoring by choosing to have electricity in her home." So it is a search.

Collecting the data is not an unreasonable search, however, when it is done with no "prosecutorial intent," the court ruled. That means that when the city is acting in its own interest in administrating and improving the electrical grid, it's perfectly reasonable for them to collect this information without a warrant. But if law enforcement wants the data, a warrant would be required.

In an increasingly IoT world, this is a very good decision.

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