Specials are taxes put onto a specific area to pay for infrastructure improvements. The city does the improvements then spreads the cost of those over the area affected. Most frequently you run into these in new subdivisions. The specials are the cost to put in the streets, curb, and street guttering. Each house is assessed a portion of these improvements and taxed to pay for them. The tax remains with the home, so you can sell it and the next buyer inherits the tax. Typical timeframe on these is 10-15 years.