Calimesa ADU rules

Maximum size

A detached ADU may have up to 1,200 sq ft of interior livable space. An attached ADU may be up to 50% of the main home's interior livable space, with no more than 1,200 sq ft added; that 1,200 sq ft limit also covers an attached ADU and a JADU together. The minimum size is 150 sq ft. A detached ADU of 800 sq ft or less with 4 ft side and rear setbacks meets all City lot coverage, floor area, open space and front setback limits. Detached ADUs of 801 to 1,200 sq ft go through a ministerial planning ADU review.

Source: Calimesa Ordinance No. 419, Exhibit A (ZTA 25-01), City Council agenda packet of February 2, 2026, § 18.20.050(L)(3)(c)-(e), (q), (L)(5)(a), accessed 2026-11-02.

Setbacks

New ADUs need at least 4 ft from the side and rear lot lines, including an ADU above a detached garage. Other ADUs use the main home's front yard setback, but a detached ADU of 800 sq ft or less is not held to the front setback. No setback is needed to convert an existing legal garage or to rebuild a structure in the same place and size. A detached ADU over 800 sq ft must be at least 10 ft from the main home and may cover no more than 30% of the required rear yard in single-family zones.

Source: Calimesa Ordinance No. 419, Exhibit A (ZTA 25-01), City Council agenda packet of February 2, 2026, § 18.20.050(L)(3)(l), (p), (q), (L)(5)(b)(iii)-(iv), accessed 2026-11-02.

Local ADU rules

Calimesa's ADU rules are in Municipal Code § 18.20.050(L) (ADUs) and (O) (junior ADUs). They were last amended by Ordinance 419 (Zone Text Amendment 25-01), adopted February 17, 2026 and in effect 30 days later. The online code (current through Ordinance 418, December 1, 2025) does not show these changes yet, so this summary uses the adopted ordinance text. ADU permits are ministerial, with no hearing, and the City acts within 60 days of a complete application.

Source: Calimesa Municipal Code § 18.20.050 Specific development standards for residential districts (eCode360), § 18.20.050(L)(2), (O)(2); Ord. 419 adopted Feb. 17, 2026 (Exhibit A, packet pp. 188-198), accessed 2026-11-02.

ADU types handled by building permit only

On a single-family lot: an ADU inside the home or an existing accessory structure (up to 150 sq ft added for entry and exit), or one new attached or detached ADU with 4 ft side and rear setbacks within the City's height limit, either of which may be paired with a JADU. On a multifamily lot: converted ADUs in non-living space (at least one, up to 25% of existing units), and detached ADUs (up to 8 on a lot with existing multifamily, not more than the number of existing units; up to 2 with proposed multifamily). ADUs that meet the state's fixed standards (Gov. Code § 66323) are not subject to the City's other development standards.

Source: Calimesa Ordinance No. 419, Exhibit A (ZTA 25-01), City Council agenda packet of February 2, 2026, § 18.20.050(L)(4)(a)-(d), (L)(9), accessed 2026-11-02.

Height

A detached ADU may be 18 ft. An attached ADU added to a home may be 25 ft or the main home's height limit, whichever is less, and an ADU above a detached garage has the same 25 ft limit. A second-story addition is allowed only if it fits these limits. An ADU built under the state's fixed standards may be 16 ft, or 18 ft within a half mile walk of a major transit stop or high-quality transit corridor (plus 2 ft to match the main home's roof pitch).

Source: Calimesa Ordinance No. 419, Exhibit A (ZTA 25-01), City Council agenda packet of February 2, 2026, § 18.20.050(L)(5)(b)(ii), (v)(1), (L)(9)(b)(ii)(4), accessed 2026-11-02.

Parking

One off-street space per ADU, which may be in setback areas or tandem and need not be covered. No space is needed within a half mile walk of public transit (including bus stops), in a historic district, for an ADU inside the home or an existing accessory structure, where on-street permits are required but not offered, within one block of a car share space, or when the ADU is filed with a new home or multifamily building. Garage or carport spaces removed for an ADU need not be replaced. ADUs under the state's fixed standards and junior ADUs need no parking.

Source: Calimesa Ordinance No. 419, Exhibit A (ZTA 25-01), City Council agenda packet of February 2, 2026, § 18.20.050(L)(3)(i)-(k), (L)(9)(f), (O)(3)(h), accessed 2026-11-02.

Design for larger ADUs

ADUs that go through planning ADU review (attached additions, detached ADUs of 801 to 1,200 sq ft, and ADUs above a detached garage) must match the main home's design, colors and materials. Windows of a second-story or above-garage ADU that face a side or rear lot line next to a home must be frosted or etched glass or the same in effect.

Source: Calimesa Ordinance No. 419, Exhibit A (ZTA 25-01), City Council agenda packet of February 2, 2026, § 18.20.050(L)(5)(b)(i), (v)(3), accessed 2026-11-02.

Junior ADUs

A JADU of 150 to 500 sq ft may be built inside a single-family home (an attached garage counts), with an efficiency kitchen and a separate entrance; if it has no bathroom of its own, it also needs an inside door to the home. No parking is needed. A restrictive covenant says the JADU cannot be sold separately or rented for less than 30 days. Ordinance 419 removed the owner occupancy requirement.

Source: Calimesa Ordinance No. 419, Exhibit A (ZTA 25-01), City Council agenda packet of February 2, 2026, § 18.20.050(O)(3)(a)-(h), accessed 2026-11-02.

Fees, utilities, sprinklers and rentals

No impact fees for an ADU under 750 sq ft; larger ADUs pay in proportion to the main home's size. An ADU inside the home or an existing accessory structure needs no new utility connection; other ADUs may be required to have one. JADUs pay no connection, capacity or impact fees. Fire sprinklers are needed only if the main home needs them. An ADU may be rented but not for less than 30 days, and may not be sold separately. A lot with an ADU may not be further divided unless it has enough land under the general plan and zoning.

Source: Calimesa Ordinance No. 419, Exhibit A (ZTA 25-01), City Council agenda packet of February 2, 2026, § 18.20.050(L)(3)(g), (m), (o), (r), (L)(6), (O)(5), accessed 2026-11-02.

Septic systems

If an ADU or JADU will connect to a septic system, the City may ask for Regional Water Quality Control Board sign-off and a percolation test from the last 5 years (10 years if the test was renewed).

Source: Calimesa Ordinance No. 419, Exhibit A (ZTA 25-01), City Council agenda packet of February 2, 2026, § 18.20.050(L)(3)(s), (O)(3)(k), accessed 2026-11-02.

Planning contact

The Planning counter at 908 Park Avenue is open 8 AM to noon, Monday through Thursday (909-795-9801). Permits are filed through the City's OpenGov permit portal.

Source: City of Calimesa Planning page, Contact Us; Planning Counter Hours, accessed 2026-11-02.