Diamond Bar, Cal., Code of Ordinances ch. 22.18 § 22.18.050

(a) Purpose. The purpose of this section is to implement the No Net Loss Law and the "no net loss" provisions of the Housing Crisis Act.
(b) Definitions. The following definitions shall apply for purposes of this section:
(1) "Housing Crisis Act" means and refers the provisions set forth in Chapter 12 of Division 1 of Title 7 of the Government Code, commencing with Section 66300, as such provisions may be amended from time to time.
(2) "Housing element parcel" means and refers to any parcel of land identified in the city's general plan housing element site inventory described in subdivision (a)(3) of Government Code Section 65583, or in a housing element program to make sites available pursuant to subdivision (c)(1) of Government Code Section 65583, for residential development to meet the city's share of regional housing need allocated pursuant to Government Code Section 65584.
(3) "Lower residential density" has the same meaning as defined in the No Net Loss Law. Except as otherwise provided in the No Net Loss Law, lower residential density means fewer residential units in any income category than were: (a) projected in the housing element site inventory to be accommodated on a housing element parcel; or (b) projected in a housing element program to be developed on a housing element parcel.
(4) "Not Net Loss Law" means and refers to the provisions of Government Code Section 65863, as such provisions may be amended from time to time.
(c) No net loss provisions applicable to all parcels where housing is an allowable use. With respect to land where housing is an allowable use, the Housing Crisis Act limits the city's authority to change the general plan land use designation, specific plan land use designation, or zoning of a parcel or parcels of property to a less intensive use or to reduce the intensity of land use within an existing general plan land use designation, specific plan land use designation, or zoning district. Therefore, notwithstanding any other provisions of this Development Code, for so long as the Housing Crisis Act continues to so limit the city's authority, the city shall not be obligated to accept or process an application for a general plan amendment, zoning map amendment, or zoning text amendment affecting a parcel on which housing is an allowable use if said application requests to change the general plan land use designation, specific plan land use designation, or zoning applicable to the parcel in a manner that would reduce the parcel's residential development capacity.
(d) No Net Loss Law provisions applicable to housing element parcels.
(1) Reductions of allowable residential density. Except as otherwise authorized pursuant to the No Net Loss Law, in addition to any other findings required pursuant to chapters 22.60, 22.70, and/or any other applicable provision of this Development Code, prior to or concurrent with approving any general plan amendment, specific plan amendment, zoning ordinance, or any other action to reduce, or require or permit the reduction of, the allowable residential density for any housing element parcel, the city council shall make written findings supported by substantial evidence of both of the following:
a. The reduction of residential density is consistent with the adopted general plan, including the housing element.
b. The remaining sites identified in the housing element are adequate to meet the requirements of Government Code Section 65583.2 and to accommodate the city's share of the regional housing need pursuant to Government Code Section 65584. This finding shall include a quantification of the remaining unmet need for the city's share of the regional housing need at each income level and the remaining capacity of sites identified in the housing element to accommodate that need by income level.
(2) Approval of development of a housing element parcel at a lower residential density.
a. Prior to or concurrent with approving an application allowing development of a housing element parcel at a lower residential density, the final review authority shall make a written finding supported by substantial evidence as to whether the remaining sites identified in the housing element are adequate to meet the requirements of Government Code Section 65583.2 and to accommodate the city's share of the regional housing need pursuant to Government Code Section 65584. This finding shall include a quantification of the remaining unmet need for the city's share of the regional housing need at each income level and the remaining capacity of sites identified in the housing element to accommodate that need by income level.
b. If the final review authority approves a development project on a housing element parcel that results in a lower residential density and does not find that the remaining sites identified in the housing element are adequate to accommodate the city's share of the regional housing need by income level, the city shall within 180 days identify and make available additional adequate sites to accommodate the city's share of the regional housing need by income level in accordance with the No Net Loss Law. This subdivision shall not be interpreted to require the city to approve an application for any permit or legislative action associated with a proposed development project. However, pursuant to the No Net Loss Law, the final review authority for a permit for a proposed housing development project may not disapprove that permit on the basis that its approval would require the city to identify and make available additional adequate sites to accommodate the city's share of the regional housing need.
(3) Applicant responsibility. If an applicant for a development project or permit requests in its initial application, as submitted, a non-residential development or a mixed-use or residential development at a residential density that would result in the remaining sites in the housing element not being adequate to accommodate the city's share of the regional housing need pursuant to Government Code Section 65584, the applicant shall assist the city to comply with the No Net Loss Law as follows:
a. The applicant shall identify and include with its application a list of additional potential candidate sites to accommodate the shortfall in the city's share of the regional housing need by income level that would result from the proposed development project, along with such evidence as is reasonably requested by the director necessary to show that such candidate sites are adequate sites pursuant to Government Code Section 65583.2 and proof that the owner or owner(s) of each such candidate site consents to rezoning and/or identification of the site in the housing element. To the extent allowed by state law, sufficient additional adequate sites must be identified before the application may be deemed complete.
b. The applicant shall fund and/or provide outreach to property owners and tenants of property within the vicinity of candidate sites as required by the director, including, without limitation, the mailing of written notices and the advertisement and conduct of community meetings to provide information to interested community members about the identification and/or potential rezoning of the candidate sites.
c. To the extent permitted by state law, the applicant shall reimburse the city for the actual fees and costs charged for the services of attorneys and/or other professional third-party consultants engaged by the city to provide consultation, advice, analysis, and/or review or preparation of documents in connection with the identification of candidate sites and determination of their adequacy pursuant to Government Code Section 65583.2 and/or the preparation and processing of any required general plan and/or zoning amendments. Concurrent with submittal of an application for the proposed development project, the applicant shall execute a reimbursement agreement with the city in a form approved by the city manager and provide a deposit to the city in an amount sufficient to cover the estimated total professional fees and costs to be incurred by the city, as determined by the director in his or her reasonable discretion. The city manager is authorized to execute said reimbursement agreement on behalf of the city.