Rancho Cucamonga, CA Accessory Structures: ADU Impact Fees (2026)
Key Facts
- Fee exemption threshold
- ADUs under 650 sq ft
- Governing sections
- Municipal Code §§ 13.08.040(F), 13.08.060(C)
- Fee calculation basis
- Net addition area plus 5-ft perimeter strip
- Fee amount source
- Set by city council resolution
- Payment timing
- At building permit issuance
Summary
Rancho Cucamonga waives its storm drainage impact fee for accessory dwelling units under 650 square feet under Municipal Code section 13.08.060(C). Larger ADUs pay a fee based only on the net square footage exceeding what an existing single-family home already covers.
Drainage fees shall not be required as a condition of the issuance of a building permit for: ... C. For single-family residences, an addition, guesthouse, or accessory dwelling unit that does not exceed 650 square feet in area... If the parcel with respect to which the building permit is issued is an existing single family residence that is required to pay drainage fee pursuant to this chapter and the permit is issued for an addition, guesthouse, or accessory dwelling unit 650 or more square feet in area, the fee shall be based on the net area of the addition, guesthouse, or accessory dwelling unit calculated as follows: the square footage of the permit application as determined by the building official plus five feet times the outside wall perimeter of the addition, guesthouse, or accessory dwelling unit.
Full Breakdown
08, and subsection (C) exempts, for single-family residences, an addition, guesthouse, or accessory dwelling unit that does not exceed 650 square feet in area. 040(F) sets the calculation: where an existing single-family residence already paid the drainage fee and the new permit covers an addition, guesthouse, or ADU of 650 square feet or more, the fee is based on the net area of that addition, calculated as the permitted square footage plus five feet times the outside wall perimeter of the addition. 070. 050. 030(B): outside the Etiwanda drainage areas, the fee is due at building permit issuance, which for an ADU means before the city issues the building permit for construction.
Violations & Fines
A building permit for an ADU 650 square feet or larger will not issue under section 13.08.030 until the calculated drainage fee is paid; there is no separate criminal penalty specific to this fee, since it functions as a permit-issuance condition rather than an ordinance violation.
Frequently Asked Questions
Does my ADU have to pay a city drainage fee?
How is the drainage fee calculated for a larger ADU?
When is the drainage fee due?
Sources & Official References
Other rules in Rancho Cucamonga
California rules heatmap·Compare Rancho Cucamonga to another location·View the California accessory structures overview
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ADU Impact Fees in Nearby Cities
How other cities in San Bernardino County handle adu impact fees.