I constantly pick up trash, call the Citizens Service Bureau, etc.

Go to the CA Bureau of Real Estate website to find out the requirements to get and maintain a license.

You may have to speak to them a few times before they make any changes.If that doesn't work, then you can call the Citizens Service Bureau and they will report the problem to the appropriate organization while you will remain anonymous.

Check with the Better Business Bureau about their track record. 

Don't value this property as a residence but as a commercial enterprise.

"But boy oh boy, we finally found a way to connect the key minimum standards of our housing code to the heart of that property owner’s business enterprise.""

When we get new tenants we give them a list of payment options including WilliamPaid - the benefit to them is that it can be reported to the credit bureau for free and helps build credit.

Its TransUnion, but yes only 1 bureau gets the reports.

Or pay for the full service screening from a credit bureau company like the one I used when I was a manager:http://www.cbacredit.com/Index.aspxI did not use them for their full service option, but, paying for a service that will check everything would be worth the money.  

The "cost" of vacancy is an operating expense and should be borne by the enterprise as a whole, from reserved funds for that purpose.