One shared wall,
a second income on your San Jose lot.

An attached ADU shares exactly one wall with your existing San Jose house. That single wall is the whole difference between this and a detached cottage sitting alone in the back yard. Past it, the unit is a complete home — a private entrance off the side or rear, a real kitchen, a full bath, a bedroom nobody crosses your living room to reach. On the tight lots you find across Willow Glen and Naglee Park, that matters. There isn't always open ground for a freestanding unit with setbacks on all four sides. An attached unit lives in the side-yard slot you already have. The trade is structural honesty: the new build ties into your roofline, your foundation and your existing wall, and on a seismic lot that tie-in is real engineering.

San Jose is the largest city in the Bay Area — the capital of Silicon Valley — and it runs its own permit shop. Your set files with the City of San Jose, not Santa Clara County and not a regional counter. Be honest about what that means: the City's review is strict, slower than a small suburb, and the fees run high. Attached units draw an extra look because reviewers study how the addition ties into your existing house, so your home's as-built condition matters more than it would on a detached job. Two things ride along everywhere here — seismic design near the Calaveras and Hayward fault systems, and the all-electric and solar-ready reach codes layered on CALGreen. State law keeps ADU review ministerial, so a complete set has to issue. Plan for that, not for a four-week miracle.