The Manufactured Home Placement Application is the form Thurston County uses when you want to place a manufactured or mobile home on private property or in a mobile home park. It is handled by the Building Development Center, part of Community Planning & Economic Development, and lists everything that must be turned in with it. On FillingPDF you can fill out the form online and download or print the completed PDF; the county publishes the original PDF and takes the application at its Building Development Center.
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What is Manufactured Home Placement Application – Thurston County, WA?
The Manufactured Home Placement Application is the Thurston County form for applying to place a manufactured or mobile home on a property. It combines a submittal checklist, project and home details, installer information, site plan requirements and an impervious surface worksheet.
The Thurston County Building Development Center, part of Community Planning & Economic Development, issues the four-page form (revision date 12/22/2025 printed in the footer). Section 2, Scope of Work, asks you to select one: Single Family Residence, Accessory Dwelling Unit (ADU), Renewal, or Mobile Home Park with a space number. Section 3 asks whether you are replacing an existing home and, if so, when it was removed.
Two parts can wait. The manufactured home details (section 4) and installer details (section 5) may be left blank until known, but must be submitted before the permit can be issued. The Impervious Surface Worksheet on page 4 lists proposed and existing impervious areas and figures the percentage of parcel coverage.
The form is used together with the county's Property Information Sheet (formerly called the Master Application), which is the first item on its checklist. Changes or remodels to a manufactured home already in place are not handled through this application: the county's forms page says they are managed by the Washington Department of Labor & Industries (LNI).
Who needs to file Manufactured Home Placement Application – Thurston County, WA?
Anyone who wants to place a manufactured or mobile home in unincorporated Thurston County through the Building Development Center uses this application. The Scope of Work section covers four situations, and you select one:
- a single family residence;
- an accessory dwelling unit (ADU);
- a renewal;
- a space in a mobile home park, with the space number.
If you are replacing an existing manufactured or mobile home, answer the replacement question in section 3 and give the date the old home was removed.
Site plan rules depend on where the home goes: section 6 applies to placement in a mobile or manufactured home park, and section 7 applies to placement on private property. The Impervious Surface Worksheet is not required for placement in a mobile home park.
This is not the form for changes to, or a remodel of, a manufactured home already in place; the county's forms page directs those to the Washington Department of Labor & Industries (LNI) at 360-902-5800. Title elimination starts with the Washington State Department of Licensing, and the county's page lists a separate Title Elimination Inspection Request for homes with no record of a placement permit.
When to file Manufactured Home Placement Application – Thurston County, WA
File the application when you are ready to apply for a permit to place the home: the checklist says all listed items are required at the time of application and that incomplete applications will not be accepted.
The application expires one year after submission unless a permit is issued. Sections 4 (manufactured home information) and 5 (installer information) may be left blank until the details are known, but they must be submitted before the permit can be issued.
Other documents may be required before issuance, and the county provides them at the time of application: the Mobile Home Data Sheet (from the Building Development Center or the Assessor's Office), the Certificate of Water Availability (COWA) if applicable, and the Well Mandate Affidavit if applicable, which is recorded with the Auditor's Office before it is submitted. The form prints no processing time.
Documents you need
- Property Information Sheet: listed first on the submittal checklist and required at the time of application.
- Site plan: required at the time of application, drawn to the Site Plan Submittal Requirements on the form (section 6 for a mobile home park, section 7 for private property).
- Septic Pumper Report: only if you are connecting to an existing septic system; the report must be within the past three years.
- State Mandate Well Form and fee: if applicable; this can be completed at the time of application.
- Impervious Surface Worksheet: required, except for placement in a mobile home park.
- Application fees: listed on the checklist as required at the time of application.
- Mobile Home Data Sheet: may be required before the permit is issued; obtained from the Building Development Center or the Assessor's Office.
- Certificate of Water Availability (COWA): only if applicable; may be required before the permit is issued.
- Well Mandate Affidavit: only if applicable; it is recorded with the Auditor's Office before it is submitted.
How to fill out Manufactured Home Placement Application – Thurston County, WA
Review the submittal checklist
Under Application Submittal Requirement Checklist, tick the Property Information Sheet, Site Plan, Septic Pumper Report (only if connecting to an existing septic system), State Mandate Well Form & Fee (if applicable), Impervious Surface Worksheet and Application Fees as you gather them.
Enter the project description
In section 1, Project Description, write a short description of the placement you are applying for.
Select the scope of work
In section 2, select one: Single Family Residence, Accessory Dwelling Unit (ADU), Renewal or Mobile Home Park. For a park, also enter the Space #.
Answer the replacement question
In section 3, check YES or NO for replacing an existing mobile or manufactured home. If YES, enter when the old home was removed from the property.
Enter manufactured home information
In section 4, give the home's year, make, model, dimensions, number of bedrooms, serial number and tax number. You may leave these blank until known, but they must be submitted before the permit can be issued.
Enter installer information
In section 5, give the installer's name, company, company address, WAINS license number and expiration date, email and phone numbers. These may also be left blank until known.
Prepare the correct site plan
For a mobile home park use the section 6 checklist (space configuration, existing and proposed structures, driveway, utilities, lot numbers and setbacks). For private property use the section 7 checklist (boundaries, structures, easements, utilities, critical areas, clearing and grading, topography, stormwater drainage, erosion control, public road apron).
Complete the impervious surface worksheet
Unless you are placing the home in a mobile home park, enter square feet for rows A to F in the Proposed (H) and Existing (I) columns, then the totals G and J, the parcel square feet in K, and the percentage in L (J divided by K).
Review and download the completed PDF
Check that every checklist item is ready and the entries match your plan, then download or print the completed PDF from FillingPDF and assemble the package described under How to submit.
How to submit Manufactured Home Placement Application – Thurston County, WA
The form names one office for the application: the Thurston County Building Development Center, Community Planning & Economic Development, 3000 Pacific Avenue, SE, Olympia, WA 98501, telephone 360-786-5490. More information is at www.thurstoncountybdc.com.
- Building Development Center: bring or send the complete package to the address above. The form prints no mailing address, online portal or appointment rule, so call 360-786-5490 to confirm how the office takes applications.
- Package contents: every item on the Application Submittal Requirement Checklist must be present, because incomplete applications are not accepted. Application fees apply; ask the Building Development Center for the current amounts and accepted payment methods.
- Well form: the State Mandate Well Form and its fee, if applicable, can be completed at the time of application.
Keep in mind that the application expires one year after submission unless a permit is issued. FillingPDF lets you fill out and download the PDF; submission follows the channels above.
Common mistakes to avoid
- Submitting without every checklist item: the form says all items are required at the time of application and incomplete applications will not be accepted.
- Using an aerial photograph or a colored site plan; the form says neither is accepted.
- Drawing the site plan on a sheet other than 11" x 17", 8 ½" x 14" or 8 ½" x 11", or without a standard engineer scale such as 1" = 30' or 1" = 100'.
- Using symbols on the site plan without a legend explaining them.
- Showing less than a 10-foot setback between the proposed home and adjacent structures in a mobile home park; the form says a minimum 10-foot setback shall be maintained.
- Attaching a septic pumper report older than three years when connecting to an existing septic system.
- Leaving out the Impervious Surface Worksheet for placement on private property; only placement in a mobile home park is exempt.
- Not submitting the manufactured home details (section 4) or installer details (section 5) before the permit can be issued, even though they may be left blank at first.
- Letting the application lapse: it expires one year after submission unless a permit is issued.
Frequently asked questions
What is the Manufactured Home Placement Application?
It is the Thurston County form for applying to place a manufactured or mobile home on a property, issued through the Building Development Center. It includes a submittal checklist, home and installer details, site plan requirements and an impervious surface worksheet.
Is this a Thurston County property tax form?
No. It is a placement application handled by the Building Development Center, not a tax return or payment form. It does ask for the home's tax number in section 4, and the Mobile Home Data Sheet can be obtained from the Assessor's Office.
What do I have to submit with the application?
The checklist requires the Property Information Sheet, a site plan, a septic pumper report (only if connecting to an existing septic system), the State Mandate Well Form and fee if applicable, the Impervious Surface Worksheet and application fees. Incomplete applications are not accepted.
Do I need the Impervious Surface Worksheet for a mobile home park?
No. The checklist says the Impervious Surface Worksheet is not required for placement in a mobile home park. For placement on private property it must be completed and submitted at the time of application.
How long is the application valid?
It expires one year after submission unless a permit is issued. The form also says the manufactured home and installer details may be left blank until known, but must be submitted before the permit can be issued.
Where do I turn in the Manufactured Home Placement Application?
The form points to the Thurston County Building Development Center, 3000 Pacific Avenue, SE, Olympia, WA 98501, telephone 360-786-5490. It prints no mailing address or portal, so call the office to confirm how it accepts applications.
Can I fill out the Manufactured Home Placement Application online?
You can fill out the PDF online on FillingPDF and download or print it. FillingPDF is independent of Thurston County and does not file the application; you deliver it to the Building Development Center yourself.
Who handles changes to a manufactured home that is already in place?
The Washington Department of Labor & Industries (LNI), according to the county's forms page, which lists 360-902-5800. This application is for placing a home, not for remodeling one already in place.
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