18VAC160-40-490. Licensee responsibility.

B. [ The licensee shall sign, date, and include his license number on all final work products prepared or reviewed and approved by the licensee. For work products performed by a journeyman licensee, the master licensee providing direct supervision shall seal, sign, date, and include his license number, along with the journeyman's signature, date, and license number on the final work product. A journeyman licensee shall not submit a work project as final without the applicable master licensee's signature, date, and license number.

Each cover page, original site plan, and final as builts should be bear the master licensee seal. 

• Your stamp or seal should be under your control at all times.
• When you place your stamp or seal on a final document, you must sign in permanent ink across the face of the stamp/seal and place the date you signed immediately next to your signature.
• When sealing or signing electronic documents, follow the board’s

Please find attached reference from licensed designers in washington.

How to get your stamp or seal

It’s your responsibility to get your stamp or seal. Request your stamp or seal from a rubber stamp company, and make sure it contains all of the following:

• State of Washington
• On-site Wastewater Treatment System Licensed Designer
• Your license number
• Your name as shown on your wall certificate
• Space to indicate the date your license expires. You may use any of the following formats:
  • EXPIRES 00/00/00
  • EXPIRES 00/00/ (year left blank to be handwritten on the document)
  • EXPIRES (entire date left blank to be handwritten on the document)

Approved design

The approved designs for on-site designer stamps and seals is shown above. You may use it in any size, as long as the stamp or seal is fully legible.

How to use your stamp or seal

• Your stamp or seal should be under your control at all times.
• When you place your stamp or seal on a final document, you must sign in permanent ink across the face of the stamp/seal and place the date you signed immediately next to your signature.
• When sealing or signing electronic documents, follow the board’s
  
  
  Purpose:  This should help protect original ownership issues and enable citizens to determine authenticity of original documents from a licensee.