What is the “RHNA” why is it important?

Each California city is required to plan for new housing to accommodate a share of regional needs. The Regional Housing Needs Assessment (“RHNA”) is the process established in State law[1] by which housing needs are determined.

Prior to each planning cycle the total new housing need for each region of California is determined by HCD based upon economic and demographic trends, existing housing problems such as overcrowding and overpayment, and additional housing needed to ensure reasonable vacancy rates and replace units lost due to demolition or natural disasters.

Diamond Bar is located within the Southern California Association of Governments (“SCAG”) region, which includes Los Angeles, Orange, Riverside, San Bernardino, Imperial and Ventura counties. The total housing need for the SCAG region is distributed to cities and counties by SCAG based upon objectives and criteria established in State law.[2]

In 2019 HCD determined that the total new housing need for the entire SCAG region in the 6th Housing Element cycle is 1,341,827 units. SCAG is currently finalizing the RHNA plan for the 6th cycle, which must fully allocate the total RHNA to jurisdictions in the SCAG region.[3] SCAG expects to adopt the final RHNA plan by February 2021.

The RHNA also distributes each jurisdiction’s total housing need into four income categories (the extremely-low and very-low categories are combined for RHNA purposes). Diamond Bar’s preliminary 6th cycle RHNA allocation by income category is shown in Table 3.

Table 3. Draft 6th RHNA by Income Category – Diamond Bar

Extremely Low + Very Low











Source: SCAG, 3/5/2020


[10] California Government Code Sec. 65584 et seq.

[11] California Government Code Sec. 65584(d)

[12] http://www.scag.ca.gov/programs/pages/housing.aspx 

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1. What is a Housing Element?
2. What is Housing Element “certification” and why is it important?
3. What are the most important issues that must be addressed in the Housing Element?
4. What is “affordable” housing?
5. What is the “RHNA” why is it important?
6. Is the RHNA a construction mandate?
7. What must cities do to comply with the RHNA?
8. Why are cities in high-cost areas expected to have affordable housing? Low-cost housing is not economically feasible here due to high land prices.
9. There is very little vacant land suitable for housing development left in Diamond Bar. Why is the RHNA allocation so high?