Tenant Lasagna Damage

[Nick Maniscalco]

One of the tenants in my duplex poured a tray of lasagna down the toilet resulting in sewage backup and $450 worth of remediation. Impossible to determine which unit is responsible and both deny they did this. Do I take the loss? Ask them both to reimburse me? Let both units know this will come out of their security deposits and they will have to replenish them? Appreciate the group's input if they have experience with tenant damage and unable to determine which unit is the offender.