Excavation in Highland Park & Mount Washington
Highland Park, in the Arroyo Seco, has the city’s largest Historic Preservation Overlay Zone at about 4,000 structures, and the Raymond Fault’s Alquist-Priolo zone crosses its north side. Neighboring Mount Washington is almost entirely Hillside Area and has had its own specific plan since 1993.
A house project inside the Mount Washington/Glassell Park Specific Plan, adopted as Ordinance 168,707 and in effect since May 10, 1993, clears City Planning first. Only after the Director of Planning grants a Project Permit can LADBS issue a building or grading permit, and on a Baseline Hillside Ordinance lot the grading permit also waits for the building permit to clear. Because the Northeast Los Angeles Community Plan area has been in the Hillside Construction Regulation district since July 2023, the job then runs under that district’s hour and hauling limits too. We map that sequence at the start so nobody orders a machine for a permit that is two approvals away.
The plan’s tree rule shapes how utility lines get routed on Mount Washington’s steep lots. Inside the dripline of a native or significant tree, a trench is dug with hand tools or small hand-held power equipment, not a backhoe. When we plan trenching for water, sewer or electrical lines, we look first for a path that stays outside driplines, and plan the hand-dug stretches as hand work when there is no way around. The same thinking applies to footings for a retaining wall cut into the slope.
Down in the Arroyo Seco, Highland Park is a different job. The Highland Park–Garvanza HPOZ was adopted in 1994 and expanded to Garvanza in 2010, and its review covers exterior work down to the landscaping. On the north side of the neighborhood the state’s Raymond Fault zone adds a separate question for new construction, and about a quarter of Highland Park is mapped by the state as liquefaction zone on lower ground. For an ADU pad in a Craftsman-era backyard, the preservation review and any soils review may both need to be settled before a shovel goes in.
Across the hills to the north is Eagle Rock, Pasadena sits up the Arroyo Seco, and Silver Lake and Echo Park are southwest past Elysian Valley.
Excavation and grading across the Los Angeles area:
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