Blythe ADU rules

Maximum size

A detached ADU on a lot with a single-family home may be up to 1,200 sq ft. An attached ADU may be up to 850 sq ft with zero or one bedroom, or 1,000 sq ft with two or more, and no more than 50% of the existing home. ADUs made entirely from space inside an existing structure or a proposed home have no size limit. Zone rules are waived as needed to allow an 800 sq ft ADU with 4 ft side and rear setbacks.

Source: Blythe Municipal Code Ch. 17.33 Accessory Dwelling Units/Junior Accessory Dwelling Units (Municode), § 17.33.060(E), (H), accessed 2026-11-03.

Setbacks

New ADUs need 4 ft side and rear setbacks and the zone's front setback. No setback is needed when an existing accessory structure is converted, or a structure is rebuilt in the same place and size. Detached ADUs must be 10 ft from other buildings on the lot, but zone standards are waived as needed to allow an 800 sq ft ADU with 4 ft side and rear setbacks.

Source: Blythe Municipal Code Ch. 17.33 Accessory Dwelling Units/Junior Accessory Dwelling Units (Municode), § 17.33.060(F), (H), accessed 2026-11-03.

Local ADU rules

Blythe's ADU rules are in Municipal Code Chapter 17.33, which was replaced in full by Ordinance 939-U (May 13, 2025) and amended by Ordinance 940 (July 8, 2025). ADUs and JADUs that meet the chapter are allowed by right with a building permit. The City acts on a complete application within 60 days without a hearing, or within 30 days when the plan matches one the City has already accepted. Where the chapter conflicts with state law, state law controls.

Source: Blythe Municipal Code Ch. 17.33 Accessory Dwelling Units/Junior Accessory Dwelling Units (Municode), §§ 17.33.010(D), 17.33.020(A)-(B), accessed 2026-11-03.

ADU types under state law

The City must act on these without other local standards: one ADU and one JADU inside a single-family home or an accessory structure (up to 150 sq ft added for entry and exit); one new detached ADU up to 800 sq ft with 4 ft side and rear setbacks, which may be paired with a JADU; converted ADUs in non-livable space of a multifamily building (at least one, up to 25% of the units); up to two detached ADUs with a proposed multifamily building; and up to eight detached ADUs with an existing multifamily building, not more than the number of existing units.

Source: Blythe Municipal Code Ch. 17.33 Accessory Dwelling Units/Junior Accessory Dwelling Units (Municode), § 17.33.080(A), accessed 2026-11-03.

Height

A detached ADU may be 16 ft. It may be 18 ft within a half mile walk of a major transit stop or high-quality transit corridor (plus 2 ft for a roof pitch that matches the main home), or on a lot with a multistory multifamily building. An attached ADU may be 25 ft or the zone's limit for the main home, whichever is lower. No ADU may be more than two stories.

Source: Blythe Municipal Code Ch. 17.33 Accessory Dwelling Units/Junior Accessory Dwelling Units (Municode), § 17.33.060(B), accessed 2026-11-03.

Parking

An ADU with at least one bedroom needs one parking space, in addition to the main home's parking. It may be tandem on an existing driveway or in a setback area. No space is needed within a half mile walk of public transit, in a historic district, for an ADU inside the home or an accessory structure, where on-street permits are required but not offered, within one block of a car share vehicle, or when the ADU is filed with a new home or multifamily building. Garage, carport or uncovered spaces removed for an ADU do not have to be replaced. JADUs need no parking.

Source: Blythe Municipal Code Ch. 17.33 Accessory Dwelling Units/Junior Accessory Dwelling Units (Municode), §§ 17.33.060(G), 17.33.070(F), accessed 2026-11-03.

Junior ADUs

One JADU is allowed inside an existing or proposed single-family home on a single-family lot, including in an attached garage, and may sit on the same lot as an ADU allowed under state law. It may be up to 500 sq ft, needs an efficiency kitchen and its own entrance on a different side of the home than the front door, and may share a bathroom (with an inside door to the home) or have its own. A recorded deed restriction is required, and the JADU may not be sold separately. No parking is needed.

Source: Blythe Municipal Code Ch. 17.33 Accessory Dwelling Units/Junior Accessory Dwelling Units (Municode), § 17.33.070, accessed 2026-11-03.

Fees, utilities, sprinklers and rentals

No impact fees for ADUs under 750 sq ft; larger ADUs pay in proportion to the main home's size. An ADU or JADU inside an existing home needs no separate utility connection or connection fee unless built with a new home; other ADUs pay a connection fee in proportion to their size or plumbing fixtures. Fire sprinklers are not needed if the main home does not need them. ADUs and JADUs may not be rented for less than 31 days, and an ADU may not be sold separately except as state law allows. The ADU's certificate of occupancy comes after the main home's.

Source: Blythe Municipal Code Ch. 17.33 Accessory Dwelling Units/Junior Accessory Dwelling Units (Municode), §§ 17.33.020(D), 17.33.050, 17.33.060(A)(3), 17.33.090(C)-(D), 17.33.100, accessed 2026-11-03.

Older unpermitted units

An ADU or JADU built before January 1, 2020 without permits may not be denied a permit for building code or ADU rule violations unless a fix is needed for health and safety or the building is substandard. No impact fees or connection charges are due for such a unit except where state law allows.

Source: Blythe Municipal Code Ch. 17.33 Accessory Dwelling Units/Junior Accessory Dwelling Units (Municode), § 17.33.030, accessed 2026-11-03.

Areas without enough water or sewer service

New ADUs are not allowed where the Public Works Director finds the neighborhood has too little water or sewer service. The City keeps a map of those areas on its website.

Source: Blythe Municipal Code Ch. 17.33 Accessory Dwelling Units/Junior Accessory Dwelling Units (Municode), § 17.33.090(B), accessed 2026-11-03.