Please see the link for California Franchise Tax Board on deducibility of Mello-Roos taxes. It depends on the nature of the Mello-Roos; mostly, you can not deduct that if it's for local benefits and improvements; but you shall be able to deduct the maintenance and repair related Mello Roos.
Here is the link http://www.ftb.ca.gov/individuals/faq/net/909.shtml
However, the best thing to do is to take to your Tax Accountant to get their professional advise.
Frank Howard Allen Reators