To avoid potentially major repair expenses and as part of routine septic system maintenance, you should have your septic tank pumped out every one to three years, depending upon how heavy the use is. Large families tend to need it done more often than small ones. The more you use the washer, garbage disposal, shower, toilet, sink, the more often you need to pump.
Thankfully, this is one project that is not possible to Do It Yourself (DIY)! (Unless you happen to own your own pumper truck) The cost to pump out a residential tank ranges from around $125 to $250. Much of the price differential is whether you need the pumper service to dig to reach your septic tank cover (as shown in the picture above) and whether you need them to actually locate the tank and cover before digging. There are some high tech methods of locating the septic tank, from radio transceivers attached to a plumbing snake to ground penetrating radar (GPR). If you need a company to come out with GPR, it will cost more than $250.