How deep your septic system needs to be into the ground depends on several factors. In extremely cold environments, the tank needs to rest below the maximum frost line, which can be up to six or eight feet deep. The standard burying depth for most systems is between a few inches and four feet below ground level. Depth can also depend on the slope of the landscaping and other property variables. 

Above ground pools are not buried in the ground. Typically, above ground pools are semi-permanent. One reason they’re more affordable is that you don’t have to dig for an inground pool and pour concrete or another material. However, you can choose to install a semi inground pool, which is a hybrid between the two.

In the United States, a depth of 36 inches (three feet) for underground water lines is the accepted industry standard. This depth varies from location to location based on local conditions. In areas with colder winters, they may be buried deeper to prevent frozen well water pipes : This is usually at least six inches below the frost level. The International Plumbing Code calls for a minimum of 12 inches below grade.

Water lines are buried at various depths, depending on the type of line. For example, most sprinkler lines are buried between four and 12 inches underground. On the other hand, water mains usually sit between one and 3 feet below ground. However, they can go even deeper in cold climates to prevent freezing.