Everything homeowners ask about building an ADU in Elk Grove — answered with 2026 data.
Yes, ADUs are allowed in All residential, agricultural-residential and agricultural zoning districts, on any lot zoned for single-family, multifamily or mixed use that has an existing or proposed dwelling (EGMC 23.90.030, 23.90.040(B)). ADUs are an accessory use and do not count toward the lot's density (23.90.030). in Elk Grove, CA. The maximum size for a detached ADU is 1,200 sq ft (EGMC 23.90.040(F)(2)); minimum 150 sq ft (23.90.040(E)). A conversion of an existing accessory structure may expand up to 150 sq ft for entry and exit (23.90.040(D)(1)). Attached ADUs can be up to 50% of the primary dwelling's floor area, but always at least 850 sq ft for a studio or 1-bedroom and 1,000 sq ft for 2+ bedrooms. Elk Grove has an ADU-friendliness score of 8/10. Check our full Elk Grove ADU rules page for complete zoning details.
ADU construction in Elk Grove typically costs $170,000-$400,000. The cost per square foot averages $250-$500. Garage conversions are more affordable at $90,000-$200,000, while prefab ADUs cost $170,000-$340,000. Permit fees add The Building Division charges a set fee per ADU for plan review, inspections and administrative time (OTC handout B-04-10) and did not publish the 2026 amount on a page readable on 9/20; ask a permit technician at (916) 478-2235 for a written estimate before you design. to your budget. See our detailed Elk Grove ADU cost guide.
Detached ADUs in Elk Grove can be up to 1,200 sq ft. Attached ADUs are limited to 50% of the primary dwelling's floor area, but always at least 850 sq ft for a studio or 1-bedroom and 1,000 sq ft for 2+ bedrooms. Junior ADUs (JADUs) have a cap of 500 sq ft, inside the walls of the single-family house, with a separate entrance and an efficiency kitchen (EGMC 23.90.050(B)-(D)). Maximum height is Attached: no taller than the primary dwelling (EGMC 23.90.040(H)); state guarantees 25 ft or the zone limit, whichever is lower (Gov. Code 66321). Detached: 16 ft where it sits in a required yard, the zone limit elsewhere (23.90.040(H)); state floor 18 ft plus 2 ft for a matching roof pitch within 1/2 mile of a major transit stop, and 18 ft on a multistory multifamily lot. Agricultural and AR zones: 30 ft (23.90.040(H)). You are allowed up to Single-family lot: 1 ADU or JADU converted from existing or proposed space plus 1 detached new-construction ADU on a qualifying lot.
Rear setback: 4 ft for new construction (EGMC 23.90.040(G)(2)); none for a conversion of existing living space or an accessory structure, or a rebuild in the same location and dimensions (23.90.040(G)(1)). Side setback: 4 ft interior side for new construction (EGMC 23.90.040(G)(2)); none for conversions or same-footprint rebuilds (23.90.040(G)(1)). Front setback: Front and street-side setbacks are those of the underlying zoning district (EGMC 23.90.040(G)(2)). Note that garage conversions may be exempt from setback requirements if the existing structure is already within the setback area.
State law caps ADU parking at 1 space per unit (Gov. Code 66314(a)(10)); the 2021 city text says 1 per bedroom, so the state cap controls. None within 1/2 mile walk of public transit including any bus stop, in a historic district, for a conversion of the house or an accessory structure, where permit parking is unavailable, or with a car-share within a block (EGMC 23.90.040(J)); tandem driveway parking allowed (23.90.040(K)); no replacement parking for a converted garage (OTC handout). Many cities and states have been relaxing ADU parking requirements in recent years. In California, no additional parking is required for ADUs near transit.
Not required for ADUs; the city's handout confirms both the house and the ADU may be rentals (OTC handout B-04-10; Gov. Code 66315). JADUs: EGMC 23.90.050(F) requires the owner to live in the house or the JADU, which under AB 1154 (in effect Jan 1, 2026) may be enforced only where the JADU shares a bathroom with the main house. Note that owner-occupancy rules vary by state law — California and several other states have eliminated this requirement for standard ADUs.
The ADU permit review timeline in Elk Grove is typically State law requires the city to approve or deny a complete ADU application within 60 days, and it is deemed approved if the city misses that (Gov. Code 66317, SB 543, since Jan 1, 2026). No average review time is published; the OTC path issues at the counter once outside-agency signoffs are in hand. Plan check: Plan check is folded into the building permit; the pre-approved city plans skip architectural review, leaving the site plan, Title 24 energy documentation and outside-agency signoffs (OTC handout B-04-10). New detached ADUs need a rooftop solar system under a separate PV permit issued after the ADU permit and finished before final inspection; sprinklers only if the main house has them (handout FAQ). Pre-approved plans availability: Yes. The city publishes its own pre-approved ADU plan set for the Over the Counter program, including a 2-bedroom 746 sq ft unit (Plan 3) issued on the 2025 California codes. The current count of plans, the 1-bedroom size and whether they remain free could not be re-read on 9/20 (city site behind a bot check); confirm with the Building Division. State law also lets you submit any plan already approved on a different lot in the same code cycle for a 30-day review (Gov. Code 65852.27).
Average ADU rental income in Elk Grove: 1-bedroom units rent for $1,900-$2,500/month, 2-bedroom units for $2,200-$3,100/month. Short-term rentals: No. An ADU may be rented separately from the house, but only for terms longer than 30 days, and it cannot be sold separately from the house (EGMC 23.90.040(I)); a JADU cannot be sold separately either (23.90.050(F)). Expected ROI: 6-12% gross rental yield on a $250,000-$400,000 detached build renting at $2,200-$3,100/mo; a $90,000-$200,000 garage conversion at $1,900-$2,500/mo can gross 11-25% (before taxes, vacancy and financing).
The minimum lot size for an ADU in Elk Grove is No minimum lot size in EGMC 23.90; the lot needs an existing or proposed dwelling (23.90.040(B)). This applies to detached ADUs — garage conversions and JADUs may have different or no lot size requirements.
Garage conversions are one of the most popular and affordable ADU options. In Elk Grove, a garage conversion typically costs $90,000-$200,000. The key advantages are lower cost (no foundation work), potential setback exemptions, and faster permitting. Read our complete garage conversion guide.
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