Height Limit

A height limit is the maximum building height that zoning allows on a given lot. It is typically measured from a defined reference point — often natural or finished grade — up to the roof, with codes specifying exactly how the measurement is taken (to the ridge, the midpoint of a sloped roof, or the top of a flat roof). Height limits control the bulk and scale of buildings and protect neighbors' access to light, air, and privacy.

Height limits are especially important for ADU projects. A detached ADU's allowable height determines whether it can be a single story or two, which directly affects how much living space fits on a small footprint — a key consideration when lot coverage or setbacks constrain the ground area. Recognizing this, many ADU-enabling laws set specific height allowances for accessory units, sometimes higher than the historic accessory-structure limit, so a two-story or above-garage unit becomes feasible.

Height interacts with the other dimensional limits to define what is buildable: setbacks fix the footprint location, lot coverage caps the footprint size, floor area ratio caps total floor area, and the height limit caps vertical extent. Where a desirable design exceeds the limit, an owner may need to redesign or, in some cases, seek a variance — a discretionary and uncertain path.

Because the exact limit, the reference point and method of measurement, and any ADU-specific allowances all vary by jurisdiction and zoning district and can change, treat this as a general overview. Confirm the current height limit and how it is measured for your specific parcel with the local planning department before you design.