Airbnb and deductions. How much of the property taxes can be deducted?

These expenses would need to be prorated based on usage for Airbnb.  If you rented out 1 room that is 200 sq. ft. for the entire year and your entire house is 2,000 sq.ft. then you would be able to deduct 10% (200/2,000) of your property taxes as a rental expense.  If you are itemizing your personal expenses, this amount will be deducted from your itemized expenses as you cannot get a double dip and get 2 deductions for the same taxes paid.

As for your well, this is a land improvement and needs to be capitalized and depreciated over 15 years.  So, using the same example above, you would be able to take 10% of the depreciation for the year.  If you paid $15,000 for the well replacement using the straight-line method of depreciation it would depreciate by a $1,000 a year (15,000/15) you would then take 10% of that $1,000 which would be $100 in depreciation expense for the year for Airbnb

If you did not rent out the room/rooms for the entire year you would need to further reduce these amounts based on the time they were used.

TurboTax will ask you all of these questions and do the calculations based on the numbers you enter and the answers you provide.