Yes, you need to register your firm's existence in the other state. This is because corporations, including LLCs, are permitted to exist at the pleasure of the state which grants their corporate status. Typically the Secretary of State's office does that for a modest fee. If you are a foreign (out of state) corporation, the other state wants to be compensated for granting you the privilege of acting as a corporation in their state.
Partnerships and sole proprietors may be seen and treated differently, since people don't have the ability to be "perpetual" as a corporation may be treated.
Since you will be a "Foreign LLC", you will need a registered agent with an address in that state, just in case the other state's S of S needs to contact you. There are companies which specialize in being registered agents. You might get a pittance of a cost reduction if you have the same overall company as your registered agent.
"IF" something bad were to happen on a project in one of those other states, one of the first things that will be asked is "were you legally providing services?" and if the answer was no, there would be business problems and likely insurance coverage problems.
Also, have you checked with the other states to see if you, as an architect registered there, can provide services without the other state asking you to also register your firm with them? Even as a Washington-registered architect, domiciled in Washington, I have to pay our board $100 or so annually for firm registration, and I'm a sole practtioner with no employees.
Ultimately the other states' Revenue department may find out that your firm exists as a foreign LLC, and may require income or excise tax in proportion of the income from projects in their state to all of your projects.
> a quarter century ago, I managed my then-firm's projects for a very good international client. Getting me registered, and getting the firm signed up with14 or so other states, was basically just a marketing activity so that we would be assigned work wherever. After that, there was an annual renewal form to complete, and another payment to the registered agents. In all that time, only two states asked for their slice of the pie for excise tax based on providing professional services there.
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Joel Niemi AIA
Joel Niemi Architect
Snohomish, WA
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