tenant in possession of marijuana

[Carlos Lez]

I do co-living rentals. So different people in different rooms. I was over at the property to show a vacant room to a prospective tenant. He and both could smell the strong unmistakable aroma of weed from a tenant's room. We have a very strong No weed policy that clearly spells no possession or growing of weed in addition to smoking or any other method of consumption in or around the house.

I run across the offending tenant who after first denying confesses to having weed in his possession.Note:  I did not catch him smoking weed. Long story short I tried to talk him into an amicable lease termination at the end of this month. He is a young chap of around 23 and brash, he refused and suggested I can go ahead and do what I want. 

This is in San Jose, CA. With all the rapidly evolving laws what do you think is my best recourse here. I am not looking for obvious replies like, serve him a 3 day notice, go to an attorney etc. In particular I am seeking pragmatic and constrictive help on how to get this guy out. Please note that this is not an apartment - rather he is renting a single room in a house and tenants in other rooms are not going to report him but will complain that they have asthma or other respiratory conditions and want to quit.

Any actionable and constructive  (operational) suggestions are much appreciated.