Seattle Density Increase Stymied by Underground Power Line Requirement

Seattle wants developers to build more housing, and has changed its zoning regulations to make that easier. 

But builders are running up against another obstacle, explains Greg Kim in The Seattle Times: a February 2025 policy from Seattle City Light required housing with four or more units to connect to the electrical grid underground. “Some builders are in an uproar, saying the process of burying wires can involve uncertain permitting timelines with multiple city departments, requiring months to years of design and engineering, and is preventing some housing from ever being built.”

Seattle City Light says the rule was prompted by broader policy changes, and that “its poles can’t physically support the added electrical load, so lines must go underground.” With new city and state laws requiring electric heat pumps and EV charging capacity in new housing, the utility says that new multifamily projects require much more power, thicker wiring, and larger transformers than single-family homes. This all adds significant weight to power poles. 

It’s unclear how much impact the undergrounding requirements are making, but Kim notes that “Seattle issued permits for 9% fewer town home and row house units in 2025 than the year before, dropping from 634 to 579, despite more lots being made available for fourplexes and sixplexes to comply with the state’s middle-housing rules.”