As of October, 2014, an official perk test, also known as a perc test or percolation test, costs anywhere from $100 to $1,000, while an unofficial perk test costs anywhere from $25 to $100. A perk test measures how efficiently the soil in an area absorbs water. An official perk test is regulated by the laws in an area, and the exact cost depends both on the size of the area to be tested and any required fees.
An official perk test is more expensive when construction equipment is required or if a county requires that the test be done by a designated employee. Unofficial perk tests can be done by any landscaper.