Monterey Park, CA Accessory Structures: ADU Impact Fees (2026)

Section 21.50.040 of Chapter 21.50, enacted by Ordinance 2261 in April 2025, sets four fee rules for ADUs. Subsection (A) makes ADUs subject to development impact fees proportional to the square footage of the primary dwelling unit, except where California law provides otherwise. Subsection (B) requires each ADU to install its own separate utility connection to the water or sewer system, subject to a connection fee or capacity charge sized to the ADU's burden on that system based on square footage or drainage fixture units, and caps that fee at the reasonable cost of providing the service, again subject to any contrary state law.

Subsection (C) lets the City charge reasonable inspection and construction fees for the permits and inspections an ADU project requires, with the fee amounts set by City Council resolution and assessed against the property owner. Subsection (D) provides the key exemption: an ADU is not treated as a new residential use for purposes of calculating connection fees or capacity charges unless it is built at the same time as a brand-new primary single-family dwelling, meaning a homeowner adding an ADU to an existing house avoids being billed as if a second new home were being connected to city utilities.

Together these four subsections tie every ADU-specific fee in Monterey Park back to the unit's actual size and its actual burden on city infrastructure rather than a flat citywide rate.