Frequency

• Tanks need pumping whenever the solid accumulation is between 30 and 50 percent of the tank’s capacity. How often your septic tank needs to be pumped out depends on a combination of factors including the size of the tank, the amount of wastewater your family generates and the amount of solids in the wastewater. North Carolina State University has a table on its website that gives estimated pumping times for different size tanks, depending on the number of people in your household.
  
  

Damage

• If you don’t pump your tank out when needed, the solids that accumulate inside the tank will overflow into the absorption field and clog your system. When this happens, wastewater can no longer flow into the soil and will, instead, flow across the ground or back-up into your house. It’s too late to pump your tank at this point. Instead, you may need to install a new absorption field.
  
  

Cost

• The cost to pump a septic tank varies, depending on where you live, but typically will cost between $200 to $300 as of publication, for a 1,000 gallon tank. This price is for a homeowner who uncovers the tank himself so the contractor can connect to the tank pumping access port. If the contractor has to uncover the tank, there will be an additional fee that may be as high as $400. In addition to paying the contractor, your fee covers the cost of sludge disposal.
  
  

The Process

• Septic tanks should be pumped from the manhole, not the inspection ports because pumping from the inspection ports may damage the tees and baffles. The contractor should use a septage spoon and backflush to loosen sludge in the corners. The contractor should not power wash the tank or leave septage in it to “seed” the tank. Once the tank is empty, it should be checked for structural damage, such as a leaking midseam, cracks or damaged baffles. You or your pumper may also be required to file a report with your municipal government.
  
  

Reducing Pump-outs

• You can reduce how often you need to pump-out your septic tank by being careful not flush anything except wastewater and toilet paper through your system. Don’t flush paper towels, disposable diapers, tissues, sanitary products or cigarette butts into your system. Reducing how much water you use will also help. Install low-flow water fixtures and repair water leaks. Don’t wash dishes under running water and turn water off while brushing your teeth.
  
  

Additives

• Using additives won’t reduce your need to pump out your system. It’s illegal to use organic chemical solvents and acids in some states. Not only don’t they work, they will damage your tank and contaminate the water. Biological additives are also ineffective because the amount of bacteria, yeast or enzymes they contain is so small you can’t see a measurable difference in how your system functions.