Liability - Having the tenants do the yard maintenece

Hi all,

Just scooped up my second 2 unit. Both of the units currently have in the lease that one set of the occupants is responsible for mowing, snow removal, etc...

Just curious....Is this a liability for me if they get hurt? Or if the other tenant slips and falls on ice because the other tenant didn't adhere to his lease responsibilities?

Thanks for the posts!

-Seth