Tenant Troubles: Can My Landlord Search My Apartment For Pot?

I'm with Dave on this one. You haven't requested services (repairs) to be done. There's no obvious leak, or other maintenance in their letter that the city building inspector would enforce, that is, a city inspector couldn't get in in or insist you allow in the landlord or repair people, based on what they've provided in their notice. If they're smelling something that suggests someone has a hoarding or cluttering issue that's unsanitary, they should call the building health inspector, whose job btw, does not include "Marijuana enforcerement".

Personally, if they respond after you've told them no the first time, I'd tell them that if they want in, they're welcome to arrive with a dept of building inspector, and try to get other tenants to let the inspector in at the same time. This way at least some repairs will be made and if they take up too much of an inspectors time, the landlord will get charged for the visits. My understanding? You, in essence, by paying rent, own the unit on the other side of your door, and you pay for repairs and maintenance as part of your rent.
They don't get to be your mommy and check on how you live, unless you're creating a nuisance, and they have to substantiate that.