How to Fill Out the Washington Mobile Food Unit Application (King and Pierce County, 2026)

This walks the actual application, field by field. For everything around it — the city business licence, fire permit, street vending and total cost — start with the Seattle food truck permit guide or the Tacoma food truck permit guide. For the statewide picture, see how to start a food truck in Washington.

Step 1 — Work out which document you are actually filling in

The form depends on the county health jurisdiction, not on the state. Washington writes the food code (chapter 246-215 WAC); each health jurisdiction writes its own paperwork, the same split as North Carolina's county-by-county application.

In both counties, plan approval comes before you build, remodel or buy a unit, and the finished unit is inspected before the annual permit is issued. If you only want to sell at a single event, TPCHD points you to a temporary food permit instead: one place, one public event, up to 21 days in a row.

Step 2 — Get the L&I insignia sequencing right

Every occupied mobile unit (a truck or trailer you work inside) needs Washington Department of Labor & Industries approval of its body, plumbing, heating and electrical work. The counties sequence it differently, and that difference decides when you can file.

• King County: Appendix B lists WA L & I Sticker # under Required Information, next to WA License Plate # and VIN #. Appendix G tells you to obtain the L&I inspection and seal prior to your plan review. The packet gives the L&I Plans Examiner's number as (360) 902-5222.
• Tacoma-Pierce: item 16 on the Plan Review Checklist asks for a photo of the L&I tag if already approved, and says it is required before final approval. The Mobile Unit Requirements add that an occupied unit must be L&I-approved before TPCHD will complete the pre-opening inspection.

So in Tacoma you can file plan review while L&I is in progress; in Seattle you cannot usefully file without the sticker number.

Step 3 — Seattle: King County's Appendix B, line by line

Appendix B is one page. The rest of the 17-page packet is the attachments it depends on, and the county will not accept the package for review until all ten are in.

Operation Information.

• Operation Name (Doing Business As).
• Mobile Unit Operating Location: Single Site or Multiple Sites/Route. If you tick Multiple, you must include all locations with the submittal.
• Scope (Briefly describe operation/menu style).
• Former Name.
• Unit Type: Cart, Vehicle, Trailer or Movable Building.
• Required Information: WA licence plate number, VIN, and WA L&I sticker number.

Plan Review Submittal Fee. Three tick boxes: New Operation, Mobile changes, Resubmitted Plan. The fee is non-refundable and cheques are payable to SKCDPH. See Step 7 before you write the amount.

Ownership Information. Are you the new owner? Yes or No, then name, business entity (Corp, LLC, etc.), mailing address and phone numbers.

Applicant Information (if different from owner). The contact person or agent who will answer the plan reviewer's questions.

Commissary Information. Business name, address, owner or contact, phone, and Sewage: Sewer or Septic System.

Restroom Information. The same fields again for the restroom you will use. The form states you must provide a restroom availability letter for each stop that lasts longer than 1 hour.

The ten items the package must contain:

1. The Appendix B application.
2. Floor plans of the unit. Front, back and side views. For an occupied unit, add scale drawings of the interior with dimensions, every piece of equipment located, surface materials, and the make and model of each piece of equipment. Appendix A also asks for a drawing of the water system: tanks, water heater, pump, tubing, waste connection and sinks. If the unit is already built, add photos of the inside, the outside, all equipment and the L&I sticker.
3. The Use of Commissary / Shared Kitchen Agreement (Appendix C), plus a drawing of the commissary showing the equipment and storage you will use.
4. The Food Preparation Flow Chart (Appendix D).
5. The Use of Restroom Agreement (Appendix E).
6. The Contact Information for Route or Site Location form (Appendix F).
7. A detailed menu, including where you buy anything you do not make yourself. The plans must carry this exact statement: "NO CHANGES WILL BE MADE WITHOUT PUBLIC HEALTH – SEATTLE & KING COUNTY APPROVAL."
8. The Mobile Operational Questionnaire (Appendix J).
9. The plan review fee.
10. The Mobile and Limited Plan Review Cover Sheet (Appendix H), placed on top.

Appendix D, the flow chart, is two grids. The first lists each menu item and ticks every step done at the commissary: thaw, cut/assemble, cook/bake, cool, cold holding, reheat, hot holding, portion/package, storage. The second ticks every step done on the unit: cold holding, cook/grill, reheat, hot holding, assemble, other. Up to ten items per grid; add a sheet if your menu is longer.

Appendix J, the questionnaire, asks how often the unit returns to the commissary, your hours at the commissary and at the sales site, where you fill and empty tanks (with the make and model of the drinking-water hose), how cold food stays at 41°F or less and hot food at 135°F or higher in transit, how the unit is powered on site, what happens to leftovers, and where the unit is stored overnight. Three answers are fixed in advance: reusable customer utensils are not allowed, all hot food is discarded at the end of the day, and no hot food is cooled on the unit.

Step 4 — Tacoma: the TPCHD application and the 62 Mobile Unit Questions

Tacoma's process uses the same plan review packet as a restaurant, plus mobile-only forms. The Plan Review Checklist (Rev. 4/15/26) lists 17 items, in this order:

1. Food Establishment Application, plus a copy of your Washington State Business License.
2. Water verification. 3. Sewer/septic verification. 4. Plan Review Questions.
3. Floor plan. 6. Equipment list, numbered to match the floor plan, commercial grade (NSF or equivalent) only.
4. Finish schedule. 8. Menu, including specials and seasonal items. 9. Food sources. 10. Food preparation steps. 11. Waste disposal form.
5. Supplemental questions (for you, the Mobile Unit Questions). 13. The fee.
6. Commissary Kitchen Agreement. 15. Sales Site Agreement for each stop over one hour. 16. L&I tag photo. 17. The commissary's floor plan, equipment list, finish schedule and water/sewer approval.

The Food Establishment Application is two pages. Page 1 asks for the opening date, facility details, the commissary address and parcel number, Are you the owner of the commissary?, the owner's corporation and individual names, the UBI number, whether you own other food establishments in Pierce County, where to send invoices, and a plan review contact. Page 2 is an hours grid for each day of the week, Annual or Seasonal, and your signature.

The form prints a warning worth taking literally: "Double check your UBI. A change in UBI requires a new application, fee, and permit." If you are about to form an LLC, form it first and apply under the LLC's UBI.

The Mobile Unit Questions (Rev. Aug 2026) are the heart of the Tacoma review. They run in this order:

• Questions 1–19, the unit and its sites. Attached floor, walls and ceiling (open-air trailers and tents are not allowed), the VIN, whether all equipment is permanently attached, whether you run a route (if yes, include a sample route), how many sales sites, a Sales Site Agreement for each one of an hour or more, restroom access and whether it needs a key, seating, daily return to the commissary, and a location plan for customers and your inspector, which can be a website or social media page.
• Questions 20–31, menu and refrigeration. How the menu is displayed, every cold beverage and where it is kept cold, whether you serve anything raw or undercooked, every raw meat cooked on the unit, how condiments are served, utensil sets and washing, whether all refrigeration is commercial grade, at least 2 refrigeration units, and a prep table if you make food to order.
• Questions 32–50, power, water and waste. How hot and cold holding is powered in transit (gas generators are not allowed while moving), hand sink dimensions, mixing faucet, the water pump's make and model and whether it pressurises to 15 psi and switches on automatically, the water heater's size, make and model, three-compartment sink dimensions, tank sizes, where you fill and empty them, trash, overnight food storage, and leftovers.
• Questions 51–56, trucks and trailers only. L&I approval, a three-compartment sink with drainboards on both ends, compartments big enough for your largest equipment, a faucet that reaches every compartment, and enough hot water to fill two compartments at 100°F without the hand sink dropping below 100°F.
• Questions 57–62, carts only. A pre-cooked menu, a sneeze-guard diagram (vertical guards at least 60 inches from the ground), and how the cart is transported and kept clean.

One inconsistency to know about: Question 41 says freshwater tanks must be at least 35 gallons for all mobile food units, while TPCHD's Mobile Unit Requirements set 5 gallons for a cart. If you are permitting a cart, confirm the figure with TPCHD before you buy a tank.

Step 5 — The commissary and restroom agreements

Both counties want a signed commissary agreement from the kitchen's owner, and both treat it as non-transferable: if either party changes, the agreement and potentially your permit fall away.

King County, Appendix C. The commissary must be an approved facility within King County, with at least a 3-compartment sink, a mop sink and a hand wash sink, and an indirectly drained food prep sink if you wash produce there. You tick which services you may use (dry storage in square feet, refrigeration, freezer, ice machine, cooking equipment, overnight truck parking, key access) and attach a scale drawing of the commissary. Changing commissary later costs $25.

Tacoma-Pierce, Commissary Kitchen Agreement. Most units need a commissary in Pierce County, and the kitchen must already hold an active commissary permit or TPCHD will not accept your application. The minimum services are potable water, wastewater disposal, garbage disposal, restroom access, a 3-compartment sink with drainboards at each end, a mop sink and a hand sink. Refrigeration and freezer space are stated in cubic feet.

Restrooms. Both counties require a plumbed restroom within 500 feet for any stop over an hour. King County's Appendix E needs hot water at 100°F or above, soap, towels and a handwashing sign, and a copy must be kept on the unit. Tacoma's Sales Site Agreement covers the same ground and adds whether electricity, potable water, wastewater disposal and overnight storage are available at the site. If you offer customer seating, King County's Appendix E and Appendix A say a plumbed customer restroom within 500 feet; the Appendix J questionnaire says 200 feet. Plan for the stricter figure.

Step 6 — The numbers both counties check on the unit

These come from the counties' requirement sheets, and they mostly agree.

Both counties also require food-grade tanks, tubing and fill hoses, a leak-free waste connection that you empty only at the commissary or another approved site, and a garbage container on the unit. TPCHD adds a pump that pressurises to 15 psi and switches on automatically.

Step 7 — What you actually pay in 2026

King County. The Appendix B form in the September 2025 packet prints $972 + $243/hr after 4 hours for a new operation. The county's 2026 Food & Facilities Program Fees sheet replaces those rates:

The permit year runs 1 April to 31 March, and a first-year permit is prorated: 100% before 1 July, 75% before 1 October, 50% before 1 January, and 25% from 1 January. Late renewals add 10%, 20% or 30% of the annual fee. The county's mobile permit page also warns that opening without the pre-operational inspection can bring fees including 50% of the annual permit fee.

Tacoma-Pierce. Fees are set by Board of Health Resolution No. 2025-4903, adopted 3 December 2025, effective 1 January 2026, and itemised on TPCHD's Food Safety Program 2026 Fees sheet in the plan review packet:

TPCHD's fee sheet has no separate mobile plan review line, so confirm with Plan Review on (253) 649-1706 which line your unit falls under. Starting construction without plan review approval costs double the plan review fee. Permits expire 31 January each year. Late invoices add 25% at 1–30 days, another 25% at 31–60 days, and at 61 days you are subject to closure.

Step 8 — Already permitted in one county? Use reciprocity

RCW 43.20.149 requires every Washington health jurisdiction, since 1 May 2020, to accept another jurisdiction's approved mobile food unit plan review if you hold a valid permit there. You supply four things: the current operating permit, the complete approved plan review, the most recent inspection report showing compliance, and your commissary agreement. The second county may also ask for restroom agreements, and for an extra commissary agreement unless you are exempt or return to your approved commissary daily. It may charge its annual permit fee but not a plan review or inspection fee.

Tacoma-Pierce's Mobile Unit Plan Review Reciprocity Checklist (Rev. Dec 2024) turns that into a list: the Food Establishment Application and business licence, the approved plan documents (menu and prep steps, floor plan, equipment list, finish schedule, water and plumbing specs, wastewater site, restroom location, operating procedures, cleaning schedule), the approval letter, the L&I approval, the primary county's permit, and its latest routine inspection report. A pre-opening inspection report does not count. You pay a processing fee, skip the pre-opening inspection, and book an appointment for the permit sticker. Reciprocity does not transfer to a new owner. King County has an equivalent Mobile Approval by Reciprocity Checklist.

The five that actually get Washington applications rejected

1. Prep steps on the wrong side of the flow chart. Knife work or produce rinsing that the county reserves for the commissary, cooling cooked food on the unit, or keeping hot food for tomorrow. Both counties forbid the last two outright.
2. Paying the fee printed on the form. King County's Appendix B still prints 2025 rates. A new unit pays $1,008 in 2026, not $972.
3. A commissary that cannot be approved. Outside King County for a Seattle unit, or a Pierce kitchen without an active commissary permit. TPCHD will not accept the application.
4. No agreement for a long stop. Every stop over an hour needs a restroom agreement (King County) or a Sales Site Agreement (Tacoma) with a plumbed restroom within 500 feet.
5. Tanks that do not clear 15%. A 35-gallon fresh tank needs at least 40.25 gallons of waste capacity, and Tacoma's floor is 42.

Sources: Public Health – Seattle & King County, Mobile Food Unit Plan Review and Permitting Guide, September 2025 (official, Appendices A–J) · King County Plan Review Application for a Mobile Food Service Unit (Appendix B) · King County Food & Facilities Program Fees, 2026 · King County mobile food business permit · TPCHD Food Establishment Plan Review packet (packet Rev. Dec 2025; checklist Rev. 4/15/26) · TPCHD Mobile Unit Requirements, Rev. Jan 2026 · TPCHD Food Establishment Application · TPCHD 2026 Fee Schedule, Resolution No. 2025-4903 · TPCHD Mobile Unit Plan Review Reciprocity Checklist, Rev. Dec 2024 · RCW 43.20.149 · King County Environmental Health 206-263-9566 (Downtown) or 206-477-8050 (Eastgate) · TPCHD Food Safety (253) 649-1706. Verified 2 October 2026.