COSA Process – Certificate of On-Site Systems Approval

A COSA (Certificate of On-site Systems Approval) is required for title transfer of lots served by on-site wells and/or septic systems. ArcTerra will complete a thorough evaluation of the property to obtain the COSA for your transfer.

ArcTerra will research MOA documentation to determine system size and design.

• Certificate will not be issued for more bedrooms than the wastewater disposal system was designed and constructed for.
•  Undocumented systems will require test hole (percolation test & groundwater monitoring), excavation of system to verify dimensions, MOA documentation and tested if adequately sized or if not, a new system will need to be installed.

ArcTerra will schedule septic tank pumping and perform the well flow and septic adequacy test.

• The well must be able to produce a minimum of 150 gallons of water per bedroom per day.
• The septic absorption field must be able to absorb a minimum of 150 gallons of water per bedroom per day.
• If the systems do not perform adequately, a new septic system and/or new well or water storage is required.
• Water samples will be taken for coliform, other bacteria, arsenic and nitrates.

ArcTerra will verify all components of the systems are functioning as they were designed.

• The client will be notified of any deficiencies and advised of the corrective actions that are necessary.

ArcTerra will verify all separation distances for all components of the well and wastewater disposal systems.

• A current as-built survey is required to verify system locations on the property.
• Encroachments will require either a waiver or removal of encroaching component.

COSA and checklist are submitted to MOA – Development Services Department for review and approval. Approval is valid for one year with current water analysis.

•  Submittal includes a non-faxed, hard copy of most recent as-built survey showing all standpipes, well, building and other improvements and well water laboratory analysis if applicable. If as-built survey does show all components of the septic/well, the surveyor must perform as-built re-certification to add missing information.