The state of North Carolina recommends every 3-5 years
Having your tank pumped regularly can also prevent solids from going to your drain field
Parking cars or moving heavy equipment over the drain field can compact the soil and damage your drain lines
Using a garbage disposal adds solids and grease to your system
More frequent cleaning may be needed if one is used
Water from roofs, driveways, or patios can overwhelm your system and cause back ups
Bacteria treatment can prevent build up of waste and avoid future problems with your system