Cal. Rev. & Tax. Code § 4985.05

(a) Notwithstanding any other law, but except as provided in subdivision (b), a property owner shall not be liable for interest or penalties, nor shall the tax collector take or continue any collection action, with respect to any ad valorem property taxes levied upon a property if the property owner satisfies all of the following requirements annually while receiving the benefit:
1. (1) The property owner supplies evidence to the tax collector that the property owner has submitted to the county assessor an application for an exemption pursuant to subdivision (g) of Section 214, including, but not limited to, the information required under Section 254.
2. (2) The property owner supplies evidence to the tax collector that they received a reservation of tax credits from the California Tax Credit Allocation Committee or an award of funds from the Department of Housing and Community Development, including a copy of the reservation letter or notice of award.
3. (3) Facilities are in the course of construction, as defined in Section 214.2 of the Revenue and Taxation Code.
(b) The treatment of delinquent installments of ad valorem property tax and associated penalties and interest under subdivision (a) shall not apply to any of the following:
1. (1) The prorated portion of any delinquent installments of ad valorem property taxes that are related to improvements not eligible for an exemption or to residential units not restricted as affordable to lower and very low income households pursuant to the reservation of tax credits from the California Tax Credit Allocation Committee or the award of funds from the Department of Housing and Community Development.
2. (2) Any late or delinquent installments of ad valorem property taxes related to property which the assessor, upon completion of its review of the application for exemption pursuant to subdivision (g) of Section 214, has deemed ineligible for exemption.
3. (3) Any delinquent installment of ad valorem taxes for property that, after four years from the date the claim for the welfare exemption was filed with the assessor, has not been developed in a manner that would make the property eligible for exemption under subdivision (g) of Section 214.
(c) An eligible property owner who is not liable for penalties or interest under this section shall provide verification of eligibility to the tax collector annually. The tax collector shall provide the list of eligible properties to the assessor.
(d) If an assessor deems an application ineligible for exemption, as described in paragraph (2) of subdivision (b), they shall make the notice required in paragraph (2) of subdivision (c) of Section 254.5 and provide a copy of the notification to the tax collector upon receipt of the annual eligibility list.
(e) Any bill, notice of deficiency, or other routine communication sent to the taxpayer from the tax collector shall not constitute a collection action under this section.
(f) This section shall apply to property tax installments that are due and payable from December 10, 2025, to April 10, 2031.