1942. (a) If within a reasonable time after written or oral notice
to the landlord or his agent, as defined in subdivision (a) of
Section 1962, of dilapidations rendering the premises untenantable
which the landlord ought to repair, the landlord neglects to do so,
the tenant may repair the same himself where the cost of such repairs
does not require an expenditure more than one month's rent of the
premises and deduct the expenses of such repairs from the rent when
due, or the tenant may vacate the premises, in which case the tenant
shall be discharged from further payment of rent, or performance of
other conditions as of the date of vacating the premises. This remedy
shall not be available to the tenant more than twice in any 12-month
   (b) For the purposes of this section, if a tenant acts to repair
and deduct after the 30th day following notice, he is presumed to
have acted after a reasonable time. The presumption established by
this subdivision is a rebuttable presumption affecting the burden of
producing evidence and shall not be construed to prevent a tenant
from repairing and deducting after a shorter notice if all the
circumstances require shorter notice.
   (c) The tenant's remedy under subdivision (a) shall not be
available if the condition was caused by the violation of Section
1929 or 1941.2.
   (d) The remedy provided by this section is in addition to any
other remedy provided by this chapter, the rental agreement, or other
applicable statutory or common law.