SEPTIC TANK PUMPING SCHEDULE – A Guide to Septic Cleaning – How Often Do You Pump Out A Septic Tank?
Table I below lists the recommended septic tank pumping frequency according to septic tank capacity and household size. The frequencies were calculated to provide a minimum of 24 hours of wastewater retention assuming 50 percent digestion of the retained solids.

The removal of septic waste by cleaning the septic tank is a critical step in septic system care as it extends the life of the septic field. Even if you don’t care how septic systems work you need to know when to clean the septic tank by pumping out septic waste. Look up your tank size and number of building occupants to see how often the septic tank should be cleaned.

Table I. Septic Tank Pumping Frequency in Years
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NOTES to the Septic Tank Pumping Schedule Table:

Numbers in the septic pumping table indicate septic treatment tank pump out in frequency of every nn years for conventional septic tanks, and assuming for year-round occupancy of the residence. (This data does not pertain to simple holding tanks which retain all solid and liquid waste with no treatment no effluent disposal system.)
* These septic tank sizes are below the minimum size allowed in Pennsylvania and other jurisdictions. Florida septic tank pumping rules and Ohio septic tank cleaning rules may be more demanding.
Minimum septic tank sizes: Under current Pennsylvania law a 900 gallon septic tank is the minimum size that must be used for a home with three bedrooms or less. If six people reside in a three-bedroom house, the tank should be pumped every 1.3 years. If the same system serves a family of two, the tank would be ready for pumping every 5.2 years. Systems installed before the current rules and regulations were implemented may need to be pumped more often, perhaps every year or less.
Garbage disposers will increase the frequency of pumping. For example, if this same three bedroom house with six residents had a garbage disposal and was generally producing a higher volume of wastewater, the pumping frequency would be calculated as follows: 1.3 years – [(0.2) x 1.3 years] = 1.0 year. For more analysis of the effect of garbage disposers on septic systems see Garbage Grinders or Garbage Disposes and Septic Tank Maintenance
Typical Septic Tank Pumping Costs: A typical fee to pump a septic tank is $200. to $300 to pump a septic tank up to 1000g in size, provided that the tank pumping access port has been uncovered and is readily accessible. If the septic pumping contractor needs to find the septic tank and then excavate the septic tank pumping access opening, expect to pay an additional $350. to $400. provided that no extraordinary measures are needed. Prices vary somewhat by region. A part of the fee you’re paying your septic pumping contractor is the cost to dispose of the septage.
For an explanation of the meaning of sewage levels in the septic tank and how that information informs septic tank pumping frequency, see SEWAGE LEVELS in SEPTIC TANKS.
Onsite sewage disposal system holding tanks, where there is no septic field, will need to be pumped more frequently based simply on the rate and volume of septic waste inflow. Portions of this information were provided by the Penn State College of Agriculture – Cooperative Extension.

We have edited and added to the original septic tank pumping guideline material based on research and field experience testing, inspecting, and installing septic systems and based on study of other reference sources on septic system maintenance and design.

Electronic Monitors for Septic Tank Scum & Sludge Levels
Below at References we also describe an electronic septic tank monitor or grease trap monitor from Worldstone. These devices can track sludge, scum, or grease levels in order to best schedule septic tank pumping or grease trap cleaning. This product is suitable for commercial installations and possibly for some residential septic tank systems.

According to the company, “Data from monitors can help establish appropriate service intervals, and document maintenance for regulatory compliance. Alarm features can help detect abnormal conditions and prevent costly backups.”The company also produces an oil tank level monitor.

Thanks to reader Robert Shirley for this tip.

OPINION – DF: this product is a great idea for commercial installations or problem septic installations. Substituting actual septic tank scum layer thickness or scum level thickness data for the septic tank pumping schedule table above may allow the tank to be opened and pumped less often – saving some money.

Watch out: But don’t forget that regular opening and inspection of the septic tank, such as happens when the septic tank is to be pumped out or “cleaned”, gives an additional opportunity to check for other septic system problems that could be leading to a costly failure, but that don’t directly concern the septic tank sludge or scum layer thickness. Examples include the discovery of lost or damaged septic tank baffles, septic tanks leaks that allow ground water to flood the septic system, or septic tank leaks out of the tank.