Many homeowners want to know how often they should have their septic system pumped. Various conditions affect when a septic tank will need to be pumped, so there is no set answer for everyone. There are, however, ways to estimate when a tank will need pumping and things you can do to extend the time before pumping is necessary. There are ways to help estimate about when you should have your tank pumped. As an example: an average 4 bedroom house may have a 1,000 to 1,200 gallon tank and with a family of 3 should expect to have the tank pumped every 3 to 5 years of typical use.