A number of [habitability] ordinances or bills have recently passed in states and cities across the U.S., including in Colorado, Los Angeles, and Minneapolis. In Nevada, a habitability law was vetoed by the governor. Habitability can be a slippery concept. There’s a general common sense idea of what makes a dwelling habitable—comfort, safety, utilities—and then there’s the legally enforceable ‘implied warranty of habitability,’ which is the legal term for a landlord’s obligation to make a rental unit livable. The latter varies between municipalities and in some places doesn’t rise to what most would consider a reasonable minimum standard. (The state of Mississippi, for example, doesn’t require landlords to provide heat in the winter or air conditioning in the summer, though they must maintain existing heating and cooling units. Arkansas doesn’t have any implied warranty of habitability at all.) In most municipalities, the implied warranty of habitability requires that units have working heat in the winter, running water, doors and windows that lock, working utilities, and no pests or environmental hazards.

But enforcement is spotty, not only because so many cities and states are cutting budgets to the bone, but also because jurisdiction over habitability can be confusing. Depending on the problem, a tenant might need to call the municipal building code office, or the Department of Health. And tenants who report their landlords over habitability issues are often retaliated against, and face a judicial system tilted heavily in favor of their landlords. “The truth is, we don’t even enforce the minimum housing code we have,” says Todd Swanstrom, a professor of public policy at the University of Missouri-St. Louis. Even where existing laws are enforced, those standards have been essentially unchanged since the 1970s—one expert told me that most habitability laws have been essentially copy-and-pasted—and are in dire need of updating.

In the big picture, many of these updated habitability bills fall into two main categories: cooling and mold. As climate change makes summer heat waves hotter and deadlier, air conditioning has become as vital as heat in the winter, but in many places local laws are a tangle of conflicting, inconsistent, and often inadequate regulations. Take the District of Columbia, for example, where landlords aren’t required to provide AC, but are required to maintain any existing AC systems. In nearby Montgomery County, Maryland, landlords are required to provide enough cooling between June 1 and Sept. 30 to keep homes below 80 degrees. Across the line in Virginia, that upper limit is set at 77 degrees, but only for certain types of rentals