Septic Tank Age Requirements

 Steel Tanks: What is required by age of tank?


0-20 years old:
Pump receipt


20-29 years old:
Inspect the tank and verify the liquid levels


Over 30 years old:
Expose 2 sides of the tank; preferably the outlet end and one side to look for leaks OR replace the tank 


Certificate of On-Site Systems Approval (COSA)

  • Issued by the Municipality of Anchorage (MOA) and serves as a confirmation to the buyer and lending institution that the well and/or septic system serving a single family or duplex home have been inspected/tested by a professioinal engineer and were found to be in compliance with the applicable standards established by the MOA.
  • Anchorage Municipal Code 16.65 requires a septic system to be sized based on the number of bedrooms in the dwelling unit(s) it serves, and assumes two occupants per bedroom.
  • For a summary of all that is included in the COSA testing process, feel free to visit the MOA's website at



Suggested Vendors for Water and Waste Systems