N.Y. County Law § 272
All real property acquired for the purposes of the county district shall be acquired in the name of such county district. Real property acquired in the name of the county district shall be assessed for the purposes of taxation at the value thereof exclusive of improvements erected or installed by or on behalf of such county district, but in no case at less than the assessed valuation at the time of acquisition by such county district, provided however, that in those cases where the county district acquires real property already containing improvements intended for the very purpose for which the particular district was established, the real property so acquired shall be assessed at the value of the land alone, exclusive of such improvements. Except as provided above, such real property shall be valued on an equitable basis with other comparable real property in the district.
N.Y. CountyLaw § 272