Check out this article from tom Copeland    http://tomcopelandblog.com/ how-to-treat-land-improvements    What do the following items have in common: outdoor fence, patio, driveway, sidewalk/walkway, underground sprinkler system, cement slab, sewer line, septic tank, underground swimming pool, and a well?
They are all considered land improvements that you can deduct as a business expense.
A land improvement is something that is attached to your land, costs more than $2,500, increases the value of the land and has a separate useful life apart from the land.
You must depreciate land improvements over 15 years. If you use the item 100% for your business you can depreciate 100% of the cost. If it’s used for both business and personal purposes, multiply the cost by your Time-Space Percentage before depreciating. If your actual business use percent is much greater than your Time-Space Percentage, you can use the actual business use percent before depreciating it. See my article “How to Calculate an Actual Business Use Percent.”