Text Size
Sunday, February 18, 2018

Certificate of On-Site Systems Approval

The Certificate of On-site Systems Approval (COSA), formally known as a health authority approval (HAA), is a certificate that is issued by the Municipality of Anchorage (MOA) which serves as confirmation to a lending institution and/or buyer that the well and/or septic system serving either a single-family residence, a single-family residence with an "accessory dwelling unit" (often referred to as an ADU), or a duplex have been inspected/tested by a professional engineer and found to be in compliance with the applicable (COSA) standards established by the Municipality of Anchorage.

In August of 1998 the Municipal Assembly passed an ordinance requiring that in order to transfer a title on any single-family residence that is served by a well and/or septic system, an HAA (now known as a COSA) must be obtained.  In September of 2012 the COSA requirement was expanded to also include single-family homes with ADUs and duplexes.  The intent of the ordinance was to help protect public health by insuring that septic systems are functional and not creating a health hazard. In addition, it ensures that well water quality is safe to drink and in sufficient quantity to meet the basic needs of the family purchasing the house.

The COSA inspection and testing process

  • Obtain records of the well and septic system from the MOA, Development Services Department (DSD). The objective is to verify if there is a documented and approved well & septic system on the property.
  • Review a copy of the as-built survey to confirm that the well and septic system are actually on the property.
  • LOCATE STANDPIPES: The first step of the site evaluation is to determine if the septic system shown in the MOA records matches the actual installation at the property. All of the septic system pipes shown in the MOA records will need to be present. If any of the pipes have been cut off and capped below grade, they will need to be found and extended above grade by the property owner prior to the arrival of the field engineer. This also applies to any pipes that are buried in the snow.
  • Field measurements are taken to verify that the required separation distances between all impacted wells and septic systems are in compliance with the separation distances in effect at the time the system was installed. If there are encroachments, then it will be necessary to apply for waivers. There are additional engineering services/charges and MOA fees associated with such waivers.
  • Verify that there is a functional monitoring tube in the drainfield so that an adequacy test can be performed. See the page entitled "Septic Adequacy Test" regarding the monitoring tubes. If one is not present a contractor will have to be hired to install one.
  • Verify that the well casing extends at least 12 inches above grade. Wells drilled after August of 1998 must extend at least 18 inches above grade. If the casing is buried below grade or in the snow it should be located by the property owner prior to the arrival of the field engineer.
  • Verify that the well wires are in conduit (protective pipe) where they extend above grade.
  • Verify the well has a functional and removable sanitary seal. If it does not, one will have to be installed.
  • Verify from the well log and or field evaluation that the well is cased and unperforated to a minimum of 40 feet, or if shallower, seated into bedrock.
  • Pull water samples and have them tested for nitrates, bacteria, and arsenic.
  • Verify that the septic tank has been pumped within the past 12 months. If not, arrange for it to be pumped. In many cases, pumping of the septic tank is necessary in order to safely run the septic adequacy test.
  • Perform well and septic system adequacy tests.
  • Complete the standardized COSA forms and submit them to the MOA for their review and approval.

If the well and or septic system are undocumented then additional engineering services will be required in order to document them to the satisfaction of the MOA.

The complete COSA process, including MOA review and approval typically takes about 4 weeks, unless a concerted effort is made to expedite the process.

COSA Costs

Septic adequacy test and well flow test (without COSA paperwork)


Septic adequacy test (without well test or COSA paperwork)


Well flow test only (without septic test or COSA paperwork)


COSA paperwork processing fee or well/septic reports (applies to new or re-issued COSA)


Water samples: arsenic, coliform bacteria, and nitrates (meets minimum COSA requirements)


RUSH Water samples: arsenic, coliform bacteria, and nitrates (meets minimum COSA requirements)


PIWA sample: For a list of contaminants, click here (includes COSA requirements)


Certificate of On-site Systems Approval processing fee (MOA charge, plus 5% markup)


Septic tank pumping in Anchorage


Septic tank pumping outside the Anchorage area


Septic system 2000 gallon pre-soak (Required if residence has been vacant for 60+ days)


Municipality of Anchorage imposed rush charge (MOA guarantees review of COSA submittal within 24 hours). Payment of this fee is necessary for all COSA submittal reviews required in less than 5 business days.


GEG, Ltd. rush charge (if the COSA is required in less than ten business days*)


*Prices are subject to change without notice 

The routine time required to complete the COSA process is roughly 30 business days. A COSA can be completed faster (possibly less than 10 days) if the water samples are expedited through the lab and the COSA paperwork is expedited through our office and the MOA. Rush charges apply at the lab, MOA, and GEG, Ltd. When an order is placed with GEG, Ltd., potential deficiencies with the well and/or septic system are unknown; therefore, we cannot predict a job's completion date. We will take all reasonable steps to perform the required services in a timely manner and will make all rush jobs our highest priority.

We encourage our clients to have their well and septic system tested as early as possible in the marketing process. Waiting until the house is sold and a closing date established before testing the well and septic system, can lead to problems if either is found to be inadequate. It is always best to identify problems early so there is adequate time to address the engineering, regulatory approval and financial aspects associated with the upgrade.

garness new logo


Garness Engineering Group, Ltd is a 100% Native American owned business enterprise.

 State of Alaska DBE Certification # 9900155

 Download Statement of Qualifications (PDF)

Product Line • Alaska Authorized Dealer
Quanics-logo logo-xerxes-2