I wish I'd have thought of this as a question for a first year law school exam! It's a great one.
Justice Willhite raises the issue concisely:
"The primary question presented in this case is: Can a landlord be
held liable to a commercial tenant for damage to the tenant’s property
resulting from an alleged sewer backup when the tenant (who had a
month-to-month tenancy in the premises after her lease expired) had
stopped paying rent, had been served (but failed to comply) with a
three-day notice to pay rent or quit, and had been named in an unlawful
detainer action filed before the alleged sewer backup occurred?"
Oooh! Good one. I could definitely see law students coming up with good arguments on both sides. Ditto for actual lawyers.
Here's how the Court of Appeal answers the question:
"We find
that the month-to-month tenancy was terminated by the tenant’s
failure to pay rent coupled with the landlord’s filing of the wrongful
detainer action. Therefore, as of the filing of the wrongful detainer
action, the tenant was a tenant at sufferance who had no lawful right to
possession of the premises. Accordingly, the landlord is not liable for
damage to the tenant’s property left on the premises when that damage
was not caused by the landlord’s intentional act or negligence."
Notice the distinction: It's not the nonpayment of rent that absolves the landlord from liability, but only the filing of the lawsuit (plus nonpayment) that creates the absolution.
You could see a variety of other possible resolutions, from the landlord still being liable (since the tenant was still in possession) to the landlord not being liable at all (because the tenant had breached by nonpayment) to the landlord not being liable only upon the date the unlawful detainer action was adjudicated in the landlord's favor. But the Court of Appeal draws a different line.
The question would still be a good one on an exam. But since the Court of Appeal has already given a pretty good answer, we'll now have to find another one.
Maybe: "Comment upon and critique the line drawn by the Court of Appeal's opinion in Multani v. Knight?"