Question on Gruzen v. Henry

[tenant]

I am located in San Francisco, CA. My roommates and I have decided to move out at the end of the month (We've given our 30 days), due to a complete lack of maintenance and upkeep that violates Civil code section 1941.1. We're also pretty sure our landlord has lost our lease without signing it, because he's called us and told us he never got it from the building manager, and she doesn't have it either.
I had a building inspector out and he has issued a notice of violation for multiple violations and work without permit, and the place has been deemed an illegal unit (I have a copy of the notice of violation). I've been reading California Tenant Law (caltenantlaw dot com / habitability, it won't let me post the direct link) which talks about Gruzen v. Henry. I wanted to verify if it really applies to my situation, because we'd like to not have to pay our last month's rent and put it towards a deposit on a new place and moving costs.
Thank you for all advice!

 

[NY_Shark]

Gruzen v. Henry is in regards to a specific ordinance in Pasadena that required the landlord to secure a certificate of occupancy. In order for Gruzen to apply here, San Francisco would have to have a similar ordinance--I don't know whether or not they do.

Gruzen does not address the implied warranty of habitability, which is really what your case is about.

As a general rule you don't have to pay rent if a unit is uninhabitable and the landlord has been aware of this for a period of time that would have given him an opportunity to repair the apartment, and even then you are allowed to make deductions.

You're allowed to withhold your rent when the unit has a "substantial reduction of habitability." I can't tell you exactly what a substantial reduction is, but I can tell you that a drippy sink and a stained carpet doesn't cut it. You can either hire a lawyer or take a leap of faith based upon what the inspector found, but if you ARE wrong you would only owe back the one month that you did not pay, as sufficient 30 day notice was given.