Septic Denial Valuation Policy

Memo to Appraisers and other interested parties

The Island County Assessor's office is required to value parcels at 100% of their true and fair market value under state law. Over recent months our office has seen a growing number of homes constructed on parcels which had previously been deemed 'unbuildable due to septic denial' and which consequently enjoyed land value assessments far below market value. With nearly 1300 parcels so categorized, an examination of the current septic denial valuation requirements and policies was undertaken. During that process, the following facts have come to the attention of the Island County Assessor's office:

  • Enhancements in septic system technology occurring as recently as 2017, (the implementation of drip irrigation/gray water septic systems) as well as other advancements such as the Glendon and Oscar systems, have rendered to buildable status many parcels previously deemed unbuildable. This represents a substantial change in market value for these parcels, as non-buildable status has historically garnered a recreational lot value in the area of $5,000-$7,000, far below what buildable lots/sites sell for resulting in an unfair tax burden shift.
  • The Island County Health Department regularly issues septic permits for construction of septic systems on parcels utilizing old site registrations which list the property as unable to support an on-site septic system.
  • An 'is not' designation shown on the Island County Health Department site registrations has historically been used as a deciding factor in determination of the development potential and market value of parcels.  
  • The Island County Health Department does not require recording of a site registrations or winter perc tests at the time they are performed. This means even though new perc tests showing a parcel previously valued as unbuildable could be conducted showing it is buildable with a much higher value, there exists no mechanism for the assessor to determine this change in status and value if an owner elects not to record it. A parcel owner could enjoy their low property valuation for years until ready to build, only then recording the new site registration and declaring the property buildable.

These discoveries necessitate a shift in policies with regard to how parcels are assigned the septic denial classification and valued as 'unbuildable due to septic denial'. The attached updated septic denial valuation policy intends to simplify and clarify under what circumstances a parcel will or will not be categorized and valued as 'unbuildable due to septic denial'.

Effective as of June 1st 2019

The below policies will be implemented regarding valuation of properties as 'unbuildable due to septic denial'

Parcels may be valued as non-buildable due to septic denial if they meet one or more of the following conditions:

  • Have a current site registration (2017 or newer) stating 'is not' capable of supporting an on-site septic, without qualification*.

*Note: Many site registrations include a qualification which may show the parcel 'IS NOT' capable of supporting an on-site septic system but then in the comments say, 'additional winter perc is required' or other similar language which requires additional action on the part of the parcel owner to make a final determination of the property's suitability for an on-site septic system. In these instances, it shall be the subsequent failure of additional requirements which entitle the parcel to a non-buildable valuation and not the mere requirement of additional testing, design, or mitigation. In other words, an 'is not*' with additional steps to take, shall be valued as buildable until those additional steps are taken and result in a final determination by the health department that the parcel truly will not support a septic.

  • Have an existing site registration on file showing less than 12" of permeable soil. 
  • Have an existing 'is not' site registration on file showing 12-18" of permeable soil**

** Note: additional consultation and review with health department required

The following parcels shall by valued as buildable unless reduction is approved by the Assessor or Chief Deputy Assessor:

  • Parcels with two or more effective usable acres when domestic water is provided from an off-site source (public, community water system, community well, shared well, etc.).
  • Parcels with five or more effective usable acres when domestic water is provided by an on-site well.
  • Parcels 5,000sf or larger with 18" or more of permeable soil depth.

If a parcel has historically been valued as 'non-buildable' under previous septic denial valuation policies and based on this updated septic denial valuation policy, the value is increased to a value reflecting its status as buildable but is subsequently deemed 'non-buildable' under modern septic regulations or due to water unavailability, the assessed value shall be supplemented and refunds issued for the current year and up to three previous years or to the start date of the new policy, whichever is shorter, regardless of when the information is provided to the assessor's office.