Seattle’s drive to add more missing-middle homes and plug new buildings into clean electricity is running into a surprisingly old obstacle: neighborhood power poles and the rules wrapped around them. Builders say new utility requirements and the steep cost of burying service lines are adding months of delay and six-figure price tags to projects that are supposed to deliver dozens of homes. The upshot is that fewer townhomes and row houses are making it from blueprints to move-in day just as the city is trying to boost housing supply and cut emissions.
Developers describe a pileup of costs and long waits for utility work. On one 24-townhome project, undergrounding and required street improvements added more than $700,000 to a $12 million budget, according to The Seattle Times. Another firm, Perpetuity LLC, says getting four homes connected to City Light took more than two years and cost more than $270,000. The same reporting shows Seattle issued about 9% fewer town-home and row-house units in 2025, dropping from 634 to 579, as reported by The Seattle Times.
City Light’s undergrounding rule
Seattle City Light adopted an internal design practice that requires new developments with four or more units to be served by underground infrastructure, a shift utility staff say is meant to keep the grid safe and ready for higher electric loads. The practice was set to be officially folded into the 2025 Requirements for Electric Service Connections on Feb. 10, 2025, and City Light says the change is intended to address voltage drops, current-carrying capacity and thermal limits as more homes electrify, per Seattle City Light.
Missing-middle meets the grid
That undergrounding rule landed on top of a broad rezone that allows four-to-six-unit missing-middle buildings in many formerly single-family neighborhoods, concentrating new electrical demand on local distribution lines. The upzoning is supposed to add housing near transit and cut emissions, but local reporting and analysis have raised questions about whether neighborhood overhead systems were ever built to handle that kind of added load, as outlined by Cascade PBS.
Long-lead civil work and incremental fixes
City Light is in the middle of a multi-year underground cable replacement program that swaps out direct-buried cable for conduit and vaults. Those big upgrades move neighborhood by neighborhood and can take years to design and build. In the meantime, many developers are still stuck with site-specific decisions, timelines and bills to bury service lines. The utility’s project pages spell out how undergrounding and related civil work layer on time and cost pressures for local developments, per Seattle City Light.
Short-term pilots and longer fixes
City officials and builders say they are pushing for workable short-term fixes while longer undergrounding and replacement projects grind forward. The Seattle Times reports that City Light plans to pilot thicker composite or fiberglass poles with a few developers this year as one shorter-term strategy, while the city and the utility look for ways to streamline permitting and share costs on electrified missing-middle projects.
The tug-of-war between clean-energy goals and the practical limits of the neighborhood grid is now shaping what actually gets built on Seattle’s residential blocks. Expect that tension, and a growing list of pilot projects, to be a running subplot as the city tries to hit its housing and climate targets at the same time.
