California has the reputation for coming up with some crazy laws that strongly and unfairly favor tenants. SB655 started out in that direction but with a lot of input from the rental housing industry I think the new law is beneficial.
Here is a summary as written by the California Apartment Association:
As initially introduced, SB 655 would have added mold to the conditions that make housing substandard. The bill was amended at CAA’s request. It now provides that a landlord has no obligation to repair a dilapidation relating to visible mold until the owner has received notice of the mold problem. The bill also holds the tenant responsible for mold that is caused by the tenant’s poor housekeeping. Under the bill, a property cannot be declared substandard unless a code enforcement officer makes the identification that the visible mold exists to the extent that it endangers the occupants. A property owner is not responsible for mold that is minor and found on surfaces that can accumulate moisture as part of their properly functioning and intended use, such as bathroom showers and the like.
In my opinion, the result of this law is a clarification of who is responsible for determining the habitability of a property when the issue of mold arises. As a property manager who has experienced wild claims, this is a welcome law.