No one gas a crystal ball to predict what any court will decide. You can expect if your LL moved to evict it would cost you money to defend, you stand at least a good chance of losing and would be unlikely to recover attorney fees.
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If you want to be the poster child for the first case argued on this subject you are welcome to do so. I'm not trying to be negative, but it is going to cost money and is pretty risky. If you look for an attorney who has a firm grasp on cannabis law issues, such as Jay Berneburg, he can call me if he wants insight on the ULD defense.
No counterclaims are allowed so long as possession is at issue, so you are fighting with both hands tied behind your back metaphorically speaking. You can recover attorney fees by statute and contract, but in my experience, it is really tough on the best facts to get fees short of the Court of Appeals.
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You don't say why you are vaporizing cannabis. If it is for medical purposes, then the landlord would be required to accommodate you under disability law.
If it is for recreation, then you would not be entitled to that protection. Although cannabis is not legal in Washington State, people do not have a "right" to use it. As a result, a landlord could prohibit its use and evict tenants for violating that rule. I think that you would have a good argument that vaporizing is not combustion.
If you within the city limits of Seattle, you have many additional protections. Seattle landlord cannot evict tenants or terminate leases without just cause. A link to an explanation of the statute is below. I don't know enough facts to guess whether you would be protected or not, but the linked document is a pretty easy read.
Unless you have a specific reason not to, your best approach might be to go to the landlord and explain your situation. You might want to put things in writing to help you organize your thoughts. That also would be helpful if the landlord later tried to evict you, and you wanted to fight it.
This is legal information and not legal advice. The final answer to your question will depend on more facts than you can include in your question and some that you probably would not think to include. Treat this as a starting point, not the answer.