Related Entries
City of Los Angeles
Prevailing Setback
Code Reference
Information Bulletin P/ZC 2002-015
LAMC 12.07.01C.1, 12.07.1C.1, 12.07C.1, 12.08C.1
LAMC 12.21C.10(a)(1) (Hillside)
Definition
The prevailing setback is a front yard setback determined not by the zone default, but by averaging the existing front yard setbacks of nearby buildings on the same block. The City of Los Angeles uses the prevailing setback rule to keep new construction visually consistent with the existing streetscape.
In any zone where the rule applies, the front yard setback shall not be less than the prevailing setback. Where a prevailing setback cannot be established — on a block with too few existing buildings or atypical configurations — the zone’s default front yard setback applies. Information Bulletin P/ZC 2002-015 describes how to perform the calculation.
On a Hillside Area lot, the prevailing setback caps at forty feet maximum and five feet minimum. On a lot fronting a Substandard Hillside Limited Street, the minimum drops to five feet by default if no prevailing setback can be established.
What flags it in plan check
Plan checkers require a block plot with the calculation. The plot shows the existing front yard setbacks of all qualifying buildings on the same side of the street and the average, rounded per the bulletin’s rules. The block plot becomes part of the approved plans.
A common surprise: the prevailing setback turns out to be longer than the owner expected. A block of older homes with deep front yards yields a deep prevailing setback, which may push a proposed new building further back than the lot or program expected. The result is a smaller buildable footprint than the zone default would have allowed.
There is a downloadable Prevailing Setback Calculator on the LADBS website. It performs the math automatically once the block’s existing setbacks are entered. A practitioner runs the calculator at concept, before any drawings are committed.
Connected Terms
Sources. Sources: City of Los Angeles Information Bulletin P/ZC 2002-015 (Determining Front Yards When Subject to the Prevailing Setback Regulation); LAMC Sections 12.07C.1, 12.07.01C.1, 12.07.1C.1, 12.08C.1, 12.21C10(a).
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