(a) Subject to subdivision (b), property shall be fully exempt from property taxation and is within the exemption provided by Sections 4 and 5 of Article XIII of the California Constitution if that property is owned and operated by a nonprofit corporation, otherwise qualifying for exemption under Section 214, that is organized and operated for the specific and primary purpose of building and rehabilitating single or multifamily residential units, if the property is subject to a 45-year recorded agreement with the appropriate local agency, and if the agreement requires all of the following:

1. (1) Requires some or all of the property’s units to be owner occupied and sold only to and purchased only by first-time homebuyers that are low-income families.
2. (2) Requires the initial downpayment on the units described in paragraph (1) to be 5 percent or less of the market value of the unit at the time of purchase.
3. (3) Requires the units described in paragraph (1) to be made available at an affordable housing cost to buyers.

(b)

1. (1) The property for which the exemption under this section is sought may be related to a larger, mixed-income development project where a portion of the units may be available to persons or families that are not low-income families. However, only the portion of the property proposed to be built or rehabilitated with units that meet the requirements under subdivision (a) shall receive the exemption. Following completion of construction, only the portion of the property with units that meet the requirements under subdivision (a) shall receive the exemption.
2. (2) On each lien date, the assessor shall adjust the exemption allowed under this section by a proration factor that reflects the portion of the property proposed to be built or rehabilitated with units that meet the requirements of subdivision (a) as a percentage of the total development. Following completion of construction, the adjustment shall reflect the portion of the property with units that meet the requirements of subdivision (a) as a percentage of the total development.

3. (3) The assessor shall assess as escaped property, pursuant to Section 532, any property for which a welfare exemption was granted pursuant to this section if either of the following occurs:

   1. (A) Construction is abandoned.
   2. (B) Upon completion of construction, the property does not meet the requirements in subdivision (a). For properties described in this subparagraph, the assessor shall assess as escaped property that portion of the property that was proposed to be, but was not, built or rehabilitated with units that meet the requirements of subdivision (a).

(c)

1. (1) In the case of property not previously designated as open space, the exemption specified by subdivision (a) shall not be denied to a property on the basis that the property does not currently include a single or multifamily residential unit as described in that subdivision, or a single or multifamily residential unit as so described that is in the course of construction.

2. (2) With regard to paragraph (1), the Legislature finds and declares all of the following:

   1. (A) The exempt activities of a nonprofit corporation as described in subdivision (a) qualitatively differ from the exempt activities of other nonprofit entities that provide housing in that the exempt purpose of a nonprofit corporation as described in subdivision (a) is not to own and operate a housing project on an ongoing basis, but is instead to make housing, and the land reasonably necessary for the use of that housing, available for prompt sale to low-income residents.
   2. (B) In light of this distinction, the holding of real property by a nonprofit corporation as described in subdivision (a), for the future construction on that property of a single or multifamily residence as described in that same subdivision, is central to that corporation’s exempt purposes and activities.
   3. (C) In light of the factors set forth in subparagraphs (A) and (B), the holding of real property by a nonprofit corporation described in subdivision (a), for the future construction on that property of a single or multifamily residence as described in that same subdivision, constitutes the exclusive use of that property for a charitable purpose within the meaning of subdivision (b) of Section 4 of Article XIII of the California Constitution.

(d) For purposes of this section, all of the following definitions apply:

1. (1) “Abandoned” has the same meaning as that term is used in Section 214.2.
2. (2) “Affordable housing cost” means a cost, with respect to low-income families, that does not exceed 30 percent of gross income.
3. (3) “First-time homebuyer” means a person who does not currently have any ownership interest in any principal residence and has not had any ownership interest in any principal residence in the three-year period prior to the date that the mortgage is executed for a unit purchased by the person described in paragraph (1) of subdivision (a) of this section. For purposes of this paragraph, “principal residence” means any property used as the person’s principal place of residence.
4. (4) “Low-income families” means very low income households, as defined in Section 50105, extremely low income households, as defined in Section 50106, lower income households, as defined in Section 50079.5, and persons and families of low income, as defined in Section 50093, and includes persons and families of extremely low income and persons and families of very low income, as those terms are used in Section 50093 of the Health and Safety Code, as those sections read on January 1, 2022.

(f)

1. (1) A nonprofit corporation making a claim for an exemption pursuant to this section shall not be eligible for the exemption under this section unless an officer of the nonprofit corporation signs under penalty of perjury an affidavit affirming to the county assessor that the property owned and operated by the nonprofit corporation is for the future construction of single or multifamily residential units on that property, as required by this section.

2. (2)

   1. (A) Notwithstanding any other law, the nonprofit corporation shall be liable for property tax for the years for which the property was exempt from taxation pursuant to this section if the property was not developed or rehabilitated, or if the development or rehabilitation is not in the course of construction, in accordance with subdivision (a) as follows:

      1. (i) In the case of property acquired by the nonprofit corporation before January 1, 2023, by January 1, 2028.
      2. (ii) In the case of property acquired by the nonprofit corporation on and after January 1, 2023, and before January 1, 2028, within five years of the lien date following the acquisition of the property by the nonprofit corporation.
   2. (B) The nonprofit corporation shall notify the assessor of the county in which the property is located if property owned by the nonprofit corporation granted an exemption pursuant to this section is not in the course of construction by the dates specified in subparagraph (A).

(g)

1. (1) This section shall be operative for lien dates occurring on or after January 1, 2023, and before January 1, 2028.
2. (2) This section shall remain in effect only until January 1, 2034, and as of that date is repealed.