If what you are asking is how do you specify that the tax-exempt interest reported in box 8 of Form 1099-INT is from Washington state, then follow the steps below: 

• On the top row of the TurboTax online screen, click on Search (or for CD/downloaded TurboTax locate the search box in the upper right corner)

• This opens a box where you can type in “interest income” (be sure to enter exactly as shown here) and click the magnifying glass (or for CD/downloaded TurboTax, click Find)

• The search results will give you an option to “Jump to interest income”

• Click on the blue “Jump to interest income” link and enter your information

• Check the My form has info in more than just Box 1 (this is uncommon) box to enter your information reported in box 8

• Click Continue and move forward until you see a screen asking Which state is your exempt interest from?

• Use the drop down box to select Washington, then click Continue

(Please add more clarification if this is not what you were asking.)