A sewer line backed up at my condo. It is a 2nd home & investment property. a total loss, & I paid a lot of $ to repair it. Can I deduct the cost of the remodel?

If it is a second home, what type of investment property?  A rental?  Going to sell it? 

In general, not you cannot deduct the cost of a remodel on a second home.  You can add it to the cost basis for when you sell it, it will lower your profit.