The pumping frequency of the tanks varies from every 2 to 5 years, depending on daily usage. During inspections, the sludge levels will be checked and intered into your file for future reference.  We will reach out to you when it is recommended to schedule a pumping. It is important to follow the pumping company's recommendations and pump all three tanks to prevent any unforeseen complications. Please remember to keep track of when the last pumping was done for future record-keeping purposes.