2 tenants multiple dogs-shared yard-lots of poop in the yard

[Julie Thevenow]

I have 4 units with a shared yard. I inherited 2 tenants with dogs(total of 7 dogs). They both have year leases that I also inherited. The leases don't have a pet clause or anything about the consequences of not picking up dog waste. I've spoken to both of them several times about picking up poop every time their dog poops. The tenant that has 4 dogs does go around the yard with a pooper scooper several times a week picking up poop. The other tenant with 3 dogs I don't think picks up after her dogs ever. I've seen them in the yard a lot unattended. So now it's mowing season and there's dog poop everywhere in the yard that I mow. I'm extremely mad about the poop in the yard. Not sure what to do all summer. Their leases expire in September.