A decade ago, mandatory renters insurance was so rare that landlords who tried to impose it risked losing tenants.

Today it’s as much a part of the rental process as a security deposit, credit check and first month’s rent.

But in the early 2000s, when the cost of property insurance for apartment owners skyrocketed, landlords sought to reduce their costs. Now a $100,000 deductible is common at large complexes. The high deductible reduces an owner’s premium, but leaves him with a hefty bill each time a tenant starts a stove fire or lets the water overflow.

The solution: File a claim against a tenant’s policy instead.

“Landlords are getting wise. They’re drafting smarter and smarter leases that allow them to go after the tenants,” says Gary Wickert, a partner with Matthiesen, Wickert & Lehrer and an expert on subrogation. “Renters insurance will hire a lawyer to defend tenants, but it also provides a target for landlords. Now the landlord has a tenant with insurance, instead of a tenant without insurance.”