Land is not depreciable, so you get no deduction for the land itself.
You may deduct the a proportion of your utility bills. You have to estimate their share of those charges, Comparing before and after bills would be one way to do that. Yo may also deduct a proportion of your real estate tax and mortgage interest.
You may depreciate the cost of the land improvements (gravel pad, line to sewer) over 15 years. Consider them 2 separate assets.
