Cal. Civ. Code § 38-12-507

(1) If
there is a breach of the warranty of habitability as set forth in section
38-12-503, a tenant may exercise one or more of the following remedies:

(a) (I) 
A tenant may terminate a rental agreement without any liability or financial
penalty to the tenant if the condition that caused the breach remains
unremedied or unrepaired and the tenant provides the landlord ten to sixty
days' written notice that states:

(A) The
uninhabitable condition or conditions that remain unremedied or unrepaired;

(B) The
tenant's intent to terminate the lease and vacate the dwelling unit; and

(C) The
date upon which the tenant intends to terminate the lease, which date must be
at least ten days after the date that the notice is provided to the landlord.

(II) If
the landlord commences or completes remedial action before the termination date
provided by the tenant in accordance with subsection (1)(a)(I)(C) of this
section, the landlord and tenant may agree, in writing at the time the
condition is being remedied or repaired or after the condition has been
remedied or repaired, to rescind the tenant's intent to terminate the lease and
continue the housing arrangement under the landlord and tenant's existing
rental agreement.

(b) (I) 
A tenant may terminate a rental agreement without any liability or financial
penalty to the tenant if a condition that caused a breach of warranty of
habitability recurs within six months after the condition was originally
remedied or repaired and the tenant, within thirty days after the condition
recurs, provides the landlord:

(A) At
least ten days' written notice that states the same uninhabitable condition has
recurred; and

(B) The
date that the tenant intends to terminate the rental agreement and vacate the
dwelling unit, which date must be at least ten days after the date that the
notice is provided to the landlord.

(II) If
the landlord commences or completes remedial action before the termination date
provided by the tenant in accordance with subsection (1)(b)(I)(B) of this
section, the landlord and tenant may agree in writing, at the time the
condition is being remedied or repaired or after the condition has been
remedied or repaired, to rescind the tenant's intent to terminate the rental
agreement and continue the housing arrangement under the landlord and tenant's
existing rental agreement.

(c) (I) 
The tenant may deduct from one or more rent payments the cost of repairing or
remedying a condition that is the basis of a breach of the warranty of
habitability, as described in section 38-12-503, if:

(A) The
tenant gives the landlord at least ten days' advance written notice of the
tenant's intent to hire a licensed or otherwise qualified professional to
remedy or repair the condition or conditions; except that the tenant may
provide only forty-eight hours' advance written notice if the tenant has a good
faith belief that the condition materially interferes with the tenant's life,
health, or safety;

(B) The
landlord fails to sufficiently remedy or repair the condition within the notice
period described in subsection (1)(c)(I)(A) of this section or the landlord
fails to provide a comparable dwelling unit or hotel room pursuant to section
38-12-503 (4);

(C) The
licensed or otherwise qualified professional is not a relative of the tenant
and provides an estimate for remedying or repairing the condition or conditions
that is reasonably consistent with industry standards;

(D) The
tenant hires the licensed or otherwise qualified professional to remedy or
repair the condition; and

(E) The
tenant provides the landlord with a receipt, invoice, or proof of payment for
work completed by the licensed or otherwise qualified professional within a
reasonable amount of time after completion of the work or within thirty days
after the landlord requests the receipt, invoice, or proof of payment.

(II) A
tenant may, in lieu of repairing a broken or malfunctioning appliance, replace
the broken or malfunctioning appliance and deduct the cost from one or more
rent payments if:

(A) The
tenant gives the landlord at least three days' advance written notice of the
tenant's intent to purchase and replace the broken or malfunctioning appliance
with a replacement appliance;

(B) The
landlord fails to sufficiently repair or replace the broken or malfunctioning
appliance within the notice period described in subsection (1)(c)(I)(A) of this
section;

(C) The
replacement appliance is of comparable quality and has substantially the same
features as the original appliance; and

(D) The
tenant provides the landlord with a receipt, invoice, or proof of payment for
the replacement appliance within a reasonable amount of time after completion
of the work or within thirty days after the landlord requests the receipt,
invoice, or proof of payment.

(III) A
tenant that deducts rental payments over two or more rental periods pursuant to
subsection (1)(c)(I) or (1)(c)(II) of this section is only required to provide
one notice to the landlord of the tenant's intent to deduct rental payments.

(IV) If
a tenant wrongfully deducts a rental payment by not substantially complying
with the requirements of this subsection (1)(c), a landlord may pursue any
legal remedy available under law. If a court finds that the tenant purposely
deducted a rental payment in bad faith, the court shall award the landlord
damages equal to double the amount of money unlawfully deducted.

(d) A
tenant may assert as a claim or counterclaim, in a court of competent
jurisdiction, a landlord's breach of the warranty of habitability as described
in section 38-12-503 and the tenant may recover actual damages directly arising
from the breach of the warranty of habitability, which shall include any
reduction in the fair rental value of the dwelling unit during any period that
the residential premises were uninhabitable pursuant to subsection (3) of this
section. A tenant may also recover court costs, reasonable attorney fees,
punitive damages, and any other damages as ordered by the court.

(e) (I) 
A tenant may obtain preliminary or permanent injunctive relief for breach of
the warranty of habitability, including an order for specific performance, in
any county or district court of competent jurisdiction. If permanent injunctive
relief or specific performance is ordered, the court's jurisdiction continues
over the matter for the purpose of ensuring compliance with the order. An order
requiring injunctive relief or specific performance may include:

(A) An
order to remedy any existing violations of this part 5, including relief to any
similarly situated tenants who are reasonably likely to be affected by the
condition as described in section 38-12-503 or by other violations of this part
5;

(B) An
order for a landlord to modify or cease practices that give rise to a violation
of this part 5; and

(C) An
order for the landlord to adopt policies or practices that ensure compliance
with this part 5 to minimize or eliminate the likelihood of future violations.

(II) In
a proceeding for injunctive relief, the court may determine actual damages for
a breach of the warranty of habitability at the time the court orders the
injunctive relief or at a later time as deemed appropriate by the court.

(III) 
If the landlord pays damages to the court pursuant to this subsection (1)(e),
and upon application by the tenant, the court shall immediately release to the
tenant the damages paid by the landlord. If the tenant vacates the leased
residential premises, the landlord shall not rent the residential premises
again until the unit is in compliance with the warranty of habitability set
forth in section 38-12-503 (1).

(f) (I) 
A tenant may obtain an immediate temporary restraining order without notice to
the landlord in any county court or district court of competent jurisdiction,
which shall require the landlord to comply with this part 5.

(II) 
The tenant's request for an immediate temporary restraining order that requires
the landlord to comply with this part 5 may be issued if the court finds, from
specific facts shown by the tenant's affidavit, verified complaint, or
testimony, that:

(A) The
tenant's dwelling unit is in a condition that materially interferes with the
tenant's life, health, or safety;

(B) The
landlord has notice of the condition;

(C) The
landlord has failed to comply with this part 5; and

(D) The
tenant certifies to the court in writing or on the record any efforts the
tenant has made to obtain the landlord's compliance with this part 5.

(III) 
The tenant's request for an immediate temporary restraining order may be
granted, dissolved, or modified in accordance with the requirements of any
applicable Colorado rules of civil procedure; except that the tenant is not
required to post security or provide proof of irreparable injury, loss, or
damage.

(IV) A
court of competent jurisdiction shall consider and rule on any motion for an
immediate temporary restraining order pursuant to this subsection (1)(f) at the
earliest possible time, and the motion takes precedence over all matters except
older motions for immediate temporary restraining orders.

(2) (a) 
If there is a breach of the warranty of habitability as described in section
38-12-503, a tenant may raise the breach as an affirmative defense to a
landlord's action for possession or an action for collection of rent.

(b) A
tenant may raise a breach of the warranty of habitability as an affirmative
defense in the tenant's answer or pretrial court filing. A court shall
liberally construe a tenant's answer or other filing to determine whether the
tenant is raising an affirmative defense.

(c) To
prove an affirmative defense as described in this subsection (2), a tenant is
not required to:

(I) 
Deposit a bond to assert or perfect a breach of the warranty of habitability as
an affirmative defense;

(II) 
Have accrued any expense related to the breach of the warranty of habitability;
or

(III) 
Have exercised any other remedy in this section in response to the landlord's
breach of the warranty of habitability, including the deducting of rental
payments as described in subsection (1)(c) of this section.

(d) (I) 
If a tenant raises a breach of the warranty of habitability as an affirmative
defense as described in this subsection (2), the court shall order that the
landlord or tenant provide any documentation relevant to the breach of the
warranty of habitability that either party requests pursuant to section
13-40-111 (6)(b) to the opposing party no less than ninety-six hours before the
day of trial. Such documentation may include any records, notices, reports,
correspondence, or other documentation maintained by the landlord in accordance
with section 38-12-503 (5).

(II) If
a landlord fails to provide all relevant documentation, the court shall order a
continuance of the trial, and repeated failure by the landlord to provide all
relevant documentation may be good cause for appropriate sanctions against the
landlord.

(III) 
If either the landlord or tenant fails to timely provide all relevant
documentation without good cause, the court may prohibit or limit the admission
of documents at trial if the court finds that the opposing party would be
substantially prejudiced by the delay in providing such documentation.

(e) (I) 
To prove the affirmative defense described in this subsection (2) in response
to an action for possession based on nonpayment of any monetary amount due
pursuant to the rental agreement, the tenant must only establish that the
landlord breached the warranty of habitability:

(A) 
Within sixty days before or at any time during the period in which the tenant
is alleged to owe rent or any other monetary amount due pursuant to the rental
agreement; or

(B) At
any time during the tenancy, and the uninhabitable condition continued to exist
into the period in which the tenant is alleged to owe rent or the monetary
amount due pursuant to the rental agreement.

(II) A
tenant does not need to demonstrate that the uninhabitable condition as
described in section 38-12-503 exists at the time of trial.

(f) (I) 
To prove the affirmative defense described in this subsection (2) in response
to an action for possession based on an alleged nonmonetary violation of the
lease, a tenant must demonstrate that the alleged nonmonetary lease violation
primarily arose from a breach of the warranty of habitability.

(II) It
is not an affirmative defense described in this subsection (2) to an action for
possession if the landlord proves the tenant committed a substantial violation
pursuant to section 13-40-107.5.

(g) If
a tenant proves an affirmative defense pursuant to this subsection (2) by a
preponderance of the evidence, the court shall:

(I) 
Deny possession to the landlord and deem the tenant to be the prevailing party,
conditioned on the payment of any rent owed to the landlord or into the court
registry within thirty days after the amount owed is determined pursuant to
subsection (2)(g)(VII) of this section;

(II) 
Order the landlord to remedy or repair any existing uninhabitable condition
within a specific time frame, including:

(A) The
continuance of any ongoing remedial action taken by the landlord;

(B) 
Compliance with any landlord obligations pursuant to this part 5;

(C) 
Specific performance or injunctive relief pursuant to subsections (1)(e) and
(1)(f) of this section; or

(D) Any
other relief the court deems necessary;

(III) 
Order a reduction in the fair rental value of the dwelling unit in accordance
with subsection (3) of this section. Any such reduction in fair rental value
applies from when the uninhabitable condition began until the condition was
remedied or repaired.

(IV) 
Order the landlord to reimburse the tenant any difference in rent between the
reduced fair rental value and any greater amount of rent that was paid to the
landlord pursuant to the rental agreement while a breach of the warranty of
habitability at the residential premises existed, regardless of whether part or
all of the rent was paid by the tenant or by a housing subsidy issued to the
tenant;

(V) 
Determine and award the tenant actual damages arising from any breach of the
warranty of habitability; except that the tenant may elect to continue the case
for further hearing on the determination and award of damages;

(VI) 
Award the tenant costs and attorney fees; and

(VII) 
Determine whether the landlord has proven that any outstanding rent is owed up
to the date of trial after adjusting the rent in accordance with the fair
rental value calculated pursuant to subsection (3) of this section and
deducting any of the following:

(A) Any
other expenses incurred by the tenant or actual damages arising from the breach
of the warranty of habitability;

(B) Any
attorney fees and court costs awarded to the tenant; and

(C) Any
awarded monetary damages arising from separate counterclaims against the
landlord that the tenant asserted and prevailed on.

(h) (I) 
If the tenant claims, but fails to prove at trial, the affirmative defense
described in this subsection (2) by a preponderance of the evidence in a
nonpayment eviction, and the landlord otherwise prevails on the landlord's
nonpayment eviction claim, the court shall provide the tenant fourteen days to
remit to the landlord or the court any amount of rent or other monetary amount
due under the rental agreement that is owed to the landlord. If the tenant pays
the amount that is owed to the landlord within fourteen days, the court shall
dismiss the nonpayment claim with prejudice. If the tenant fails to pay the
amount that is owed within fourteen days, the court may enter a judgment for
possession.

(II) If
the court determines that the tenant brought the affirmative defense
frivolously or for the purpose of delay, the court's judgment for possession is
not subject to the fourteen-day waiting period in accordance with subsection
(2)(h)(I) of this section.

(3) If
a court or jury finds a breach of the warranty of habitability, then the fair
rental value of the dwelling unit is rebuttably presumed to be:

(a) 
Zero dollars if the underlying condition or combination of conditions
materially interferes with the tenant's life, health, or safety as described in
section 38-12-503 for the entire period in which the condition or conditions
remained unremedied or unrepaired; or

(b) 
Fifty percent of the rent according to the rental agreement if the underlying
condition or combination of conditions does not materially interfere with a
tenant's life, health, or safety as described in section 38-12-503 for the
entire period in which the condition or conditions remained unremedied or
unrepaired.

(4) If
a rental agreement contains a provision that allows a prevailing party in an
action related to the rental agreement to obtain attorney fees and costs, and
if the court determines that there is a prevailing party, then the prevailing
party in an action brought under this part 5 is entitled to recover reasonable
attorney fees and costs; except that a court shall only award a landlord
reasonable attorney fees and costs if the court finds that a tenant has filed a
frivolous complaint or counterclaim under this part 5.

(5) (a) 
A rental agreement or other agreement between a landlord and a tenant entered
into on or after May 3, 2024, that waives or modifies a right or remedy
provided in this part 5 is unlawful, void, and unenforceable, including any
provision in a rental agreement or other agreement that charges a cost, fee, or
penalty to a tenant because the tenant exercised or attempted to exercise a
right or remedy provided in this part 5.

(b) The
exercise of one or more rights or remedies provided in this section does not
limit a tenant's rights to exercise or attempt to exercise any other right or
remedy provided by law.

(c) A
written notice required by a remedy described in this section is valid if it
substantially complies with the requirements of this section.