If you sell your property in the U.S. you must file a federal and state tax return to report the sale.
If renting, rental properties in the U.S. require annual nonresident tax return 1040NR to report gain or loss from rental activity.
Annual non-resident state return is required as well unless property is located in a tax-free state like TX.
Annual reporting is required even if you generate a loss. Furthermore, when you choose to sell your property, all accumulated losses (if any) are deducted from sales proceeds. Without annual reporting, these losses cannot be recovered. If property is idle (no rental activity), no reporting is required.