See this TurboTax
discussion of Mello-Roos taxes. While most of the Mello-Roos assessments are not deductible (those that relate to local benefits), if there are any assessments that are for a general benefit for the entire community under the taxing authority, they would be deductible.
SuperUser Opus provides insight on this issue.
https://ttlc.intuit.com/replies/6436101