Thorough percolation reports submitted to the county for review are key to preventing delay of approval. Percolation reports with supporting data, schematics, maps and details will also benefit the owner by enabling well-informed bids from installation contractors. In many cases a non-recorded system can become satisfactorily documented with the use of ground-penetrating radar (GPR). GPR can augment other geophysical tools to provide a much better map. In many cases these