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Sunday, January 21, 2018

Well & Septic Testing

Well and Septic testing may be required for many different reasons. The most common reasons for testing a well and/or septic system are:

  • Certificate of On-site Systems Approval - A certificate issued by the MOA which serves as confirmation to lending institutions that the well and/or septic system, serving a single family residence, have been inspected by a professional engineer and have been found to be in compliance with the applicable standards. Please see our COSA page for more specific information.
  • Multi-family - When purchasing a duplex or any other type of multi-family dwelling, it is a good idea to have the well and/or septic system tested and evaluated. Any information regarding these systems will aid in your purchasing decisions.
  • Personal Interest - There are many different reasons why a septic system may be causing problems. If it is backing up inside or surfacing outside, it would be a good idea to have a professional examine the system.

Septic Testing

What is a septic system adequacy test (SAT) and why is it performed? The purpose of an SAT is to determine whether a drainfield can continually absorb the daily introduction of wastewater from a residence. Obviously, if a drainfield cannot absorb wastewater at an adequate rate, eventually it will backup into the residence or overflow onto the yard creating a health hazard. If more information is needed on septic systems, please visit our Description of a Typical Septic System page.

Learn More..

Well Flow Testing

What is a well adequacy test (WAT) and why is performed? Typically, the purpose of a WAT is to determine whether a well is able to meet the production requirements established by the State of Alaska and/or the Municipality of Anchorage for the residence served. In some cases it will be necessary to meet even more demanding flow requirements in order to satisfy the lending institution, particularly the Federal Housing Authority (FHA).


State and Municipal Well Production Requirements:


Per State and Municipal regulations, a well must be capable of producing at least 150 gallons per day, per bedroom. This corresponds to the following minimum flow rates:


  • Five (5) bedrooms: 0.52 gallons per minute = 750 gallons per day
  • Four (4) bedrooms: 0.42 gallons per minute = 600 gallons per day
  • Three (3) bedrooms: 0.31 gallons per minute = 450 gallons per day
  • Two (2) bedrooms: 0.21 gallons per minute = 300 gallons per day


These minimum flow rates have been established to meet only household uses and do not account for watering lawns/gardens, washing cars, or filling your new king size Jacuzzi tub. Consequently, if the flow rate of the well meets only minimum standards, it may be necessary to install water storage tanks, which serve as a reservoir to supplement the well production during peak flow requirements. It is common for residential water systems with low producing wells to have 500-1000 gallons of water storage. These tanks are often located in a crawl space or in the garage. A storage tank, the supplemental jet pump, and the associated controls can add several thousand dollars to the water system cost.


Wells which do not meet the aforementioned minimum flow standards must be equipped with a water storage system. Per the 1998 Municipal well ordinance, if the flow rate is less than the required amount, but greater than 150 gallons per day, a 500 gallon storage tank is required. If the daily production of the well is less than 150 gallons per day, a 1000 gallon storage tank is required.


The primary reason for the storage tank is to allow for potable water to be delivered to the house on an as-needed basis. There are several companies that deliver potable water, typically charging a fee based upon the number of gallons purchased.


FHA Financing


If the property is being financed by the FHA, the water system must be capable of producing at least 3 gallons per minute per dwelling unit. This corresponds to 3 gpm for a single family residence, 6 gpm for a duplex, and 9 gpm for a triplex (and so on......). If the well is incapable of producing this amount of water, the deficiency can be made up for by adding storage tanks.


Well Production Can Vary Seasonally


It is important to know that well production can vary seasonally, and sometimes quite dramatically. Wells will typically produce better in the late spring, after the aquifer is recharged by the snowmelt, and in the late fall (mid October) after the aquifer is recharged from the August/September rains. It is also possible that well production will decline in the middle of the winter, because the aquifer is not being recharged by melting snow or rainfall. Given these facts, it is reasonable to assume that if a well barely meets minimum flow standards in late spring, there is a good chance that its production will be below minimum standards in January and February. If you are purchasing a property with a low production well, this fact will be of particular significance.


How Long is the Well Test Data Considered Valid?


The MOA considers that data from the adequacy test to be valid for up to two (2) years. Consequently, they will issue a HAA based upon the data for up to two (2) years after the testing date.


How is the Well Test Performed?


Prior to starting the test the field engineer removes the protective cover (called a sanitary seal) off of the top of the well and measures the distance from the top of the casing down to water. This measurement is typically made with an instrument called an acoustic well sounder (AWS). The AWS is placed over the top of the well and activated. The activated AWS bounces a sound signal down to the water level and back to the AWS where the distance is internally calculated and shown on an electronic display. This measurement is recorded by the field technician. The test then proceeds as follows:


  1. A hose is connected so as to by-pass any water storage tanks connected to the water system. This may require some plumbing modifications if it is not possible to isolate the storage tanks from the well.


  1. A water meter is connected to the hose and the meter reading is recorded by the field technician.


  1. The water is turned on. Throughout the pumping period the drop in the water level in the well is measured at numerous time intervals and recorded. In addition, the water meter readings are simultaneously recorded.


  1. Pumping is continued until the well produces enough water to meet/exceed the required minimum daily flow rate. The flow is then turned off and the recovery of the water level in the casing measured and recorded at various time intervals, typically over several hours.


  1. If the well runs out of water before the minimum flow rate can be established, the field engineer will deactivate the pump by turning off the electrical breaker in the house, and allow the well to recover for a period of time (typically about 30-60 minutes). The well will then be reactivated, deactivated, rested, and reactivated over several cycles, until the recovery rate can be established by the field engineer.


  1. The above acquired data will be used by the engineer to establish well production rate.


What if My Well is Found to be Inadequate?


The performance of a low production bedrock well can often be enhanced by a process referred to as hydrofracturing. Hydrofracturing is performed by well drillers or well pump service companies. The objective of the process is to fill the well with water and pressurize it so as to fracture the surrounding bedrock and open up paths for groundwater to reach the well. Hydrofracturing costs several thousand dollars and is often successful in obtaining at least some increased production, however, there are no guarantees. If the well's production is still inadequate, the installation of storage tanks can be used to bring the water system into compliance with any regulatory and/or lending institution requirements.


I Am Selling or Refinancing My House. When Should I get the Well Tested?


If you are selling your house, it is recommended that you have the well tested as early as possible in the marketing process. This way, if there are any deficiencies, there is time to get them resolved to the satisfaction of the MOA, the lender, and most importantly, the buyer.


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.


Ideally, reading the topics addressed in this site will help you to make more informed decisions regarding the testing/upgrade of your well or septic system, or the purchase of a property served, or to be served, by an onsite well or septic system. The information presented within this site should not be used as a basis for any decisions regarding the purchase of a property or upgrading your well or septic system. Prior to making any such decisions, you should consult directly with your engineer, real estate agent, and/or attorney.

We hope you find this information useful. If you have additional questions, please feel free to contact us directly.

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

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