A special assessment tax is a surtax levied on property owners to pay for specific local infrastructure projects such as the construction or maintenance of roads or sewer lines. The tax is charged only to the owners of property in the neighborhood that will benefit from the project. That neighborhood is called the special assessment district.

Prospective homebuyers should be aware of any special assessment tax on a property they are considering. Special assessments may be levied for a pre-set number of years, and they are often not tax-deductible.

Like property taxes, special assessment taxes are based on the assessed value of the home.