Along with determining the age of the system, we review records of previous inspections. Older systems may not have been reviewed or noted, or have any records available. On the other hand, newer systems may have complete records that make it easier to review and identify problems. Flow can be estimated based on the number of bedrooms in the building compared with the number of current residents and patterns of water use. T he septic tank holds a wealth of information about the operation and performance of the entire on-site system.
Some states use the tank as the single point of information about and entire system.
Although the inspection will include examinations of other system components, we start by opening the tank and looking into it. For many tanks that means opening the 20-inch manhole in addition to any other manholes on the top of the tank. For other tanks it means taking a section of the lid off. We have to be able to see the inside of the tank, so opening the four-inch inspection pipe will not be sufficient. Then we pump the tank.