In Los Angeles, ADU Designers Are Doing "The Electric Slide"

Like true love, the practice of architecture doesn’t always run smoothly. But Ben Warwas faced a sizable hitch when designing a backyard house, or ADU, in L.A.’s Mar Vista neighborhood: the power lines overhanging the rear lot line. Since the architectural designer’s clients were committed to converting their garage into a two-story ADU, placing it in proximity to the L.A. Department of Water & Power’s height restrictions, Warwas now had to find a way to work around the lines.

Though overhead power lines pose a challenge to architects and designers around the U.S., they’re especially problematic in L.A., where more ADUs are being built than anyplace else. Since grounding power lines can be prohibitively expensive, and require a coordinated effort between utility providers and neighbors, designers and builders of ADUs across the Southern California city are instead coming up with novel workarounds for lines coursing through backyard airspace.

Often it requires clever positioning of a unit or adjusting the massing in some way—something architect Melissa Shin calls "the electric slide." She encountered her own utility issue on an ADU currently under construction on L.A.’s West Side, a standalone, two-story unit designed to take advantage of California’s reduced rear and side yard setback requirements for new detached ADUs.

Since there was a power pole at the rear of the property, Shin, the principal at Shin Shin, had to apply for an encroachment permit with the DWP’s Real Estate Services division. After four months she received notice the application had been rejected. "Our first submission was for an ADU set as far back as we could go, but they came back and told us we either had to move it or reduce the height," she says. "At that point, the building was already approved through plan check, so to go back and shave off five feet, you’re basically starting over."

Instead, she just moved it. Since the pole sat on the property itself, Shin ended up with a nine foot, six inch overall setback. "So even though the minimum allowable ADU setback is four feet, which is significantly less than any other type of construction, we couldn’t take advantage of it."

Architect Hunter Knight, founder and principal of Weather Projects, remembers a far simpler process before the current ADU building boom. "Four or five years ago, a DWP clearance for building near electrical lines wasn’t required. But with ADUs being so close to lot lines, people would start construction, and they’d call DWP and say they needed a meter spot [where the utility company verifies where you can install your new or upgraded electric service panel]. And DWP might come out and say, ‘Your building’s too close to the power lines. It’s a safety issue.’ And you’d say, ‘Whoops, we didn’t know.’ And they’d say, ‘You were supposed to contact us.’ And we’d say, ‘We were? We went through the whole Building & Safety plan check—we thought we were good.’ So they made it a clearance in Building & Safety."

Though there are only two ways to bring power from utility infrastructure to an ADU—overhead or underground—homeowners connecting power to an ADU via an electric service drop from the pole still have to underground the line between the unit and the primary residence. But Knight warns that if the overhead connection for the drop is too far from the transformer, the solution is costly, in terms of both money and time. "And if the overhead line is routed over a habitable area, you have to pay for DWP to engineer that, and you pay for the underground routing from the pole," he says. "That’s where things get really expensive. That almost got triggered for an ADU I designed in Cypress Park, but in the end, the DWP decided they didn’t need to underground the line after all."