Tenant refusing to pay share of DWP utilities...

[Carolina Provvido]

Yesterday my landlord client reached out regarding one of her tenants refusing to pay her share of the DWP bill, which is meant to be divided equally among all the units. The lease agreement explicitly states that each tenant is responsible for their portion of the bill. Any advice on courses of action my client can pursue? The unit is in Los Angeles and it seems like landlord rights are diminishing. Any suggestions?