It depends. Check with your local county health department concerning regulations governing septic tank pumping as related to selling and purchasing of a home. Some counties require documentation showing that a septic tank has been pumped out by a licensed septage hauler within a reasonable amount of time prior to the sale or purchase of a property. If too much time has passed or no proof is found, you may be required to have the tank pumped in order to complete the sale or purchase of the real estate. Such regulations help insure that the septic system is functioning properly and is not creating a nuisance condition. This also gives the potential buyers of the property an accurate date to use in determining when to schedule their routine pumping every 3 to 5 years.