Most Fremont ADU surprises come from water, sewer, and the 500 sf school fee, not the City permit

What to check before paying for ADU plans in Fremont: the FUSD school fee at 500 sf, ACWD water, Union Sanitary sewer, and Fremont's own fire department.

If you're thinking about building an ADU in Fremont this year, the expensive surprises usually do not come from the City permit itself. They come from the service questions around the lot, especially water, sewer, and whether your ADU crosses Fremont Unified's 500 square foot school fee threshold before anybody priced that into the budget. What FUSD changed, and why 500 square feet matters As of May 24, 2026, Fremont Unified School District raised its school fee to $5.38 per square foot for ADUs over 500 square feet. That number matters because a lot of homeowners still budget as if school…