Septic Components - Inspection Risers/Ports
Inspection ports, or inspection risers, are vertical pipes that terminate at the bottom of a leach trench, and can be opened at the ground surface for inspection. They are found at the end of leach lines, and are required to be installed with all new septic systems. 
Inspection ports are helpful in monitoring the activity of your septic system. You can monitor the use of each leach line and whether a line is full or not.
It is important to protect your system from surface water, so always keep your inspection port cap on. Also, the pipe extending to the surface should be solid and not perforated. For specific installation instructions, please review the County's Private Sewage Disposal Systems Ordinance, or call your local Environmental Health Specialist at (530) 621-5300.
Inspection port, or inspection riser,
in a trench prior to gravel backfill. Notice the
perforated pipe to solid pipe transition in the trench.
The perforated pipe will be below the filter material
This illustration shows an inspection port / inspection riser installed in a typical gravel-filled leach line:
Inspection ports do not have to be visible in your yard. You can have the port "hidden" in a plumbing box, and it can still be easily accessible for inspection.
The illustration below shows an inspection port / inspection riser installed in a typical gravel-less/infiltrator leach line:
