They wouldn’t put a fire hazard in a 5 and 6 year olds class room where we live.According to your theory your tenants shouldn’t have a stove, hair or clothes dryer, or anything that could cause damage to your units it sounds like.

If the clog was tenant-caused then tenant is responsible for the damage.

As a past realtor and a contractor I have never heard that the landlord would have to pay for their property if damaged or stolen.

It is typically available in the sale of land, but otherwise is not generally available if damages are an appropriate alternative.Mediation as @Russell Brazil mentioned might be a good idea as well. 

Does anyone know of any database (or website) that allows a landlord to report a "bad tenants", i am not talking about credit agency. just a simple database that allows a landlord to report a tenant that caused damages or did not pay rent?

Mine, that I can think of off the top of my head:During a rehab, I leave all the old front/rear door knobs and deadbolts on, which are usually mismatched and sometimes damaged.

But I do second the vinyl planks... what's amazing about those is that you can re-use the flooring if you ever have water damage.

I worked at an apartment complex where we rented by the bedroom and it's very important to outline policies regarding the security deposit, shared common areas, damage charges, etc. 

A bad tenant that fails to pay rent for one month and leaves the place damaged could easily cost you $5,000 - $10,000.

Unfortunately the guy can do a lot of damage to a property, really in no time at all.If this were my problem I would be on point at the location with a private security service as well as local PD, camera in hand and rolling the entire time.