Parcels with Onsite Sewage Designations in King County

Metadata also available as - [Outline]

Frequently anticipated questions:

What does this data set describe?

Title: Parcels with Onsite Sewage Designations in King County
Project was to find, count and map onsite septic system (OSS) served parcels in King County. Additionally, sewer connected parcels were also identified to exclude them from expected OSS parcels. The starting base layer was a parcel layer for all of King County (Plibrary.PROPERTY.parcel_area) from about September of 2015. Project staff used various means to identify and catalogue sewer connected, OSS served, vacant and other identified parcels for all of King County.
Corrections to this data set will be made and as additional information is received, processed and edited in the attributes of this set. There is no timeframe on when these changes will occur, and will occur as needed.
  1. How should this data set be cited?

    County, King, 20171128, Parcels with Onsite Sewage Designations in King County: King County, King County, WA.

    Online Links:

    • None

    Other_Citation_Details: None

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -122.550396
    East_Bounding_Coordinate: -121.084384
    North_Bounding_Coordinate: 47.788447
    South_Bounding_Coordinate: 47.072060

  3. What does it look like?

    <> (JPG)
    JPG File of layer overlain on base of WA counties or local cities

  4. Does the data set describe conditions during a particular time period?

    Calendar_Date: 31-Aug-2021
    Currentness_Reference: Ground Condition

  5. What is the general form of this data set?

    Geospatial_Data_Presentation_Form: vector digital data

  6. How does the data set represent geographic features?

    1. How are geographic features stored in the data set?

      This is a Vector data set. It contains the following vector data types (SDTS terminology):

      • GT-polygon composed of chains (624835)

    2. What coordinate system is used to represent geographic features?

      The map projection used is NAD 1983 HARN StatePlane Washington North FIPS 4601 Feet.

      Projection parameters:
      Standard_Parallel: 47.5
      Standard_Parallel: 48.73333333333333
      Longitude_of_Central_Meridian: -120.8333333333333
      Latitude_of_Projection_Origin: 47.0
      False_Easting: 1640416.666666667
      False_Northing: 0.0

      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 0.0005
      Ordinates (y-coordinates) are specified to the nearest 0.0005
      Planar coordinates are specified in foot_us

      The horizontal datum used is D North American 1983 HARN.
      The ellipsoid used is GRS 1980.
      The semi-major axis of the ellipsoid used is 6378137.0.
      The flattening of the ellipsoid used is 1/298.257222101.

  7. How does the data set describe geographic features?

    area data table (Source: King County)

    Internal feature number. (Source: Esri)

    Sequential unique whole numbers that are automatically generated.

    Parcel Identification Number (Source: King County)

    Ten digit identifier, may begin with leading zeros

    Type of wastewater system like sewer connection, OSS, or also Vacant, Water, etc. (Source: King County)

    Integer value decoded in ExpExcludeOn

    Sewer connection Yes, or NULL (Source: King County)

    Integer value decoded in ExpSewerConnection

    Sewer Agency serving this sewer connected parcel (Source: King County)

    Integer value decoded in ExpSewerAgency

    Parcel is or was listed on Capacity Charge table Yes, or NULL (Source: King County)

    Capacity Charge status unknown
    YesParcel is or was listed on Capacity Charge Table

    Connection source verified by, other comments regarding property and or connection (Source: King County)

    Free text




    Feature geometry. (Source: Esri)

    Coordinates defining the features.



    The attributes define whether a parcel is served by septic, sewer, is vacant, or otherwise does not require sewage service.
    Entity_and_Attribute_Detail_Citation: King County

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)

  2. Who also contributed to the data set?

    Environmental Health Services, Public Health Seattle & King County

  3. To whom should users address questions about the data?

    Public Health - Seattle and King County
    Attn: Peter Isaksen
    Project Manager
    401 5th Ave, Ste 1100
    Seattle, WA 98104

    206-263-8479 (voice)

Why was the data set created?

The purpose of this data set is to manage a list of OnSite Septic System (OSS) parcels in King County.

How was the data set created?

  1. From what previous works were the data drawn?

  2. How were the data generated, processed, and modified?

    Date: 01-Sep-2015 (process 1 of 2)
    Copy made of PARCEL_AREA from September 2015. Added fields to data design to capture information about status of the parcel.

    Date: 30-Dec-2016 (process 2 of 2)
    Assembled various ancillary datasets. Used these data to update the status of the parcel.The status was generated by excluding known sewer connected parcels as well as parcels that are vacant, have no living structures that would require sewage, and or parcels that are not living unit containing like water, forest, parklands, etc. Various data sources were used for the initial analysis including Aerial photos, Oblique photos, and Assessors data and other county and city datasets as needed. Coordination with the 42 Sewer Agencies within King County was used to help identify the sewer connected parcels. Also, the Capacity Charge program shared their data to provide additional proof of sewer connections since this charge is paid by property owners that connect to the sewer system and that are billed for this connection over 15 years. Although this data set is intended to only track actual OSS parcels, the sewer connected parcels will be updated as new and or corrected lists, or other evidence is provided. Since parcels do change over time, it is expected that the parcel layer will be updated, as needed, and that a new parcel layer will be substituted. This will require a process to identify parcels that no longer exist, as well as parcels that are newly created. These changes will be tracked so that this file, as well as other OSS databases can be edited for these changes.

  3. What similar or related data should the user be aware of?

How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?

    The accuracy of the data is dependent on the quality and accuracy of the additional data sources and lists received. Corrections will be made as needed, especially when new or better evidence is received.

  2. How accurate are the geographic locations?

    Positional accuracy dependent on the state of PARCEL_AREA at the time of initial data editing

  3. How accurate are the heights or depths?

  4. Where are the gaps in the data? What is missing?

    This data set is intended only for the parcels that are within the King County Boundary

  5. How consistent are the relationships among the observations, including topology?

    The parcel data set originally used has changed over time, and will require updating to maintain a connection with current real world locations.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?

Access Constraint: Data is not available on GIS Data Portal, it may be available via a custom data request
Use Constraint: King County data are made available with the understanding that they shall be used exclusively by the obtainer or his/her authorized agents. Digital products may not be reproduced or redistributed in any form or by any means without the express written authorization of King County.

  1. Who distributes the data set? (Distributor 1 of 1)

    KCGIS Center
    Data Distribution
    201 S Jackson St
    Seattle, WA 98104

    206-477-4403 (voice)

  2. What's the catalog number I need to order this data set?


  3. What legal disclaimers am I supposed to read?

    Distribution Liability: King County disclaims any warranty of use of any digital product or data beyond that for which it was designed.

  4. How can I download or order the data?

Who wrote the metadata?

Last modified: 30-Sep-2021
Metadata author:
Public Health - Seattle and King County
Attn: Peter Isaksen
Project Manager
401 5th Ave, Ste 1100
Seattle, WA 98104

206-263-8479 (voice)

Metadata standard:
FGDC Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)

Generated by mp version 2.9.12 on Sun Oct 17 11:59:11 2021