The City of Riverside (not the unincorporated County of Riverside, which has its own rules) approves ADUs, junior ADUs (JADUs) and movable ADUs (MADUs) with a ministerial building permit under Riverside Municipal Code Chapter 19.442, last amended by Ordinance 7743 (effective December 4, 2025). A detached ADU may be up to 1,200 sq ft and 20 ft tall (30 ft if two-story), an attached ADU up to 50% of the main home or 1,200 sq ft, and a JADU up to 500 sq ft inside the house; new one-story units need only 4-ft side and rear setbacks, no parking, no minimum lot size, and their floor area does not count toward lot coverage. A single-family lot may combine one attached or converted ADU, one detached new-construction ADU (or MADU) and one JADU. Fees are valuation-based rather than flat, impact fees are waived at 750 sq ft or less, and the city's Dwell Riverside program offers four free permit-ready plans (746-1,200 sq ft) with a 3-business-day first plan review; state law caps the city's decision at 60 days.
Outside city limits? If your property is in unincorporated Riverside County (not within Riverside's boundaries), different rules apply — see our Riverside County (unincorporated) ADU rules.
Zoning & Size Requirements [1][2][3][4][5][6][7][8]
Yes — Riverside allows ADUs. A detached ADU can typically be up to 1,200 sq ft under current California and Riverside zoning rules.
See what this means for your lot — ask Riverside ADU builders for a quote →
| Allowed Zones | All residential zones and all multifamily and mixed-use zones with an existing or proposed dwelling (RMC 19.442.020). Permitted-use Table 19.150.020.A lists ADUs and JADUs as permitted (P) in the RC, RA-5, RR, RE, R-1, R-3, R-4, MU-N, MU-V and MU-U zones and not in the O, CR, CG, CRC, BMP, I, AI, AIR, PF and RWY zones. JADUs only on lots with a single-family home. Designated or eligible cultural resources and historic-district lots also need a Certificate of Appropriateness under Title 20 and must follow the 2025 ADU Design Standards for Historic Properties; MADUs are barred there |
| Max Size (Detached) | 1,200 sq ft of floor area (RMC 19.442.030(D)(2)). A movable ADU (MADU, a unit on a chassis) must be 150-430 sq ft measured to the outside of the exterior walls (D)(3). Any ADU must be at least the size of an efficiency dwelling unit under California Building Code 1208.4 (D)(5). ADU floor area is not counted toward lot coverage (A)(8) |
| Max Size (Attached) | 50% of the existing or proposed primary dwelling's floor area or 1,200 sq ft, whichever is less, including converted floor area; the 50% cap can never block an ADU of 850 sq ft (one bedroom or fewer) or 1,000 sq ft (two or more bedrooms) (RMC 19.442.030(D)(1), as amended by Ord. 7701). Converting an existing house or accessory structure has no separate size limit beyond these caps |
| Max Size (JADU) | 500 sq ft, built entirely within the walls of the existing or proposed single-family house (an attached garage counts as inside the walls), with its own exterior entrance, an efficiency kitchen, and either its own bathroom or a shared one with the main house (RMC 19.442.030(B)(5), (D)(4); Gov. Code 66333) |
| Max Height | Detached one-story ADU or MADU: 20 ft. Two-story detached ADU, or an ADU on the second floor of an existing accessory building: 30 ft (RMC 19.442.030(G); the city's ADU FAQ says the same). Attached ADU: the underlying zone's height limit, which is 35 ft and two stories in the R-1, RR, RE and RA-5 zones (Residential Zones handout A8). In the RC (Residential Conservation) zone any detached ADU is limited to 20 ft and one story. These exceed the state minimums of 16 ft (18 ft within a half mile of a major transit stop, plus 2 ft for a matching roof pitch) for detached and 25 ft for attached ADUs (Gov. Code 66321(b)(4)) |
| Max Units | Single-family lot: the main house plus one attached or converted ADU, one detached new-construction ADU or MADU, and one JADU (RMC 19.442.030(E)(1), as clarified by Ord. 7743). Existing multifamily: conversions of non-living space equal to at least 1 and up to 25% of existing units, plus up to 8 new detached ADUs (never more than the number of existing units); proposed multifamily: 2 detached ADUs (E)(2). MADUs are not allowed on multifamily lots. Two-unit (SB 9) lots follow Chapter 19.443 |
Setback Requirements [1][2][3][4][5][6][7][8]
Riverside requires a rear setback of about 4 ft for a detached ADU, and no additional parking is required. Owner-occupancy is not required — you can rent it out without living on the property.
| Rear Setback | 4 ft for a new one-story ADU or MADU up to 16 ft tall, measured from the rear lot line and from other buildings; a taller or two-story new ADU, or a new second story added to an existing structure, must meet the base zone's rear setback (RMC 19.442.030(C); city ADU FAQ). No added setback for converting an existing structure or an existing second story. State law caps side and rear setbacks at 4 ft for any new ADU (Gov. Code 66314(d)(7)) and guarantees a detached ADU of at least 800 sq ft with 4-ft setbacks at 16 ft (18 ft near major transit), so ask the Planning Division before assuming a larger setback applies to a taller unit |
| Side Setback | 4 ft for a new one-story ADU or MADU up to 16 ft tall; above 16 ft or for a second-floor ADU in a new structure, the base zone's side setback applies (RMC 19.442.030(C)(2)). Street-side setbacks follow the base zone. Conversions of existing structures need no additional setback, and the setback must always be enough for fire and safety access (C)(3) |
| Front Setback | A new ADU or MADU must meet the base zone's front and street-side setbacks (RMC 19.442.030(C)(2)(b)): 20 ft in R-1-7000, 25 ft in R-1-8500, R-1-10500 and R-1-13000, 30 ft in R-1-1/2 acre, RE, RR and RC, and 40 ft in RA-5 (Residential Zones handout A8). ADUs are not allowed in the front yard, and a MADU may not sit between the house and the street (B)(2). Conversions inside the existing house or an existing accessory structure keep their current setbacks, and a front setback cannot be used to block an 800 sq ft ADU with 4-ft side and rear setbacks (Gov. Code 66321(b)(3)) |
| Parking Required | None. No parking space is required for an ADU, MADU or JADU, and no replacement parking is required for the main house when a garage, carport or covered parking is converted to an ADU (RMC 19.442.030(H)) |
| Owner Occupancy | Not required for an ADU or MADU on a lot with the primary home (RMC 19.442.030(F)(a)). For a JADU the city code requires the owner to live in either the main house or the JADU and to record a deed restriction; since January 1, 2026 state law (Gov. Code 66333(b), AB 1154) allows that requirement only when the JADU shares a bathroom with the main house, so a JADU with its own bathroom should be exempt: confirm with the Planning Division. Every JADU needs a recorded deed restriction barring separate sale (A)(10) |
| Min Lot Size | No minimum lot size to establish an ADU, MADU or JADU (RMC 19.442.030(A)(7)), and the city cannot require you to fix existing zoning nonconformities first (A)(6) |
Permit Process & Fees [9][10][11][12][13][14][15][16][17][18][19][20]
An ADU permit in Riverside goes through a ministerial, by-right review. Typical timeline: Permit-ready plans: 3 business days for the first review, 10 for rechecks. Custom ADUs (Tier 2): 20 working days first review, 10 for resubmittals; paid expedited review can halve that. State law: complete applications decided within 60 days (Gov. Code 66317, SB 543). Permit fees: Valuation-based, not flat: roughly $1,400-$1,500 in Building & Safety permit and plan-check fees for an 800 sq ft ADU on the FY2023-24 schedule ($100.04/sq ft valuation), plus Planning's $289 zoning check and surcharges; the city's 2022 workshop put all-in fees at $3,000-$9,000.
| Approval Process | Ministerial building permit, no hearing or environmental review, through the Community & Economic Development Department's One Stop Shop (3900 Main St, 3rd floor, 951-826-5800), applied for online on the Riverside Public Permit Portal. Custom designs: a plan set from a licensed design professional with site plan, floor plan, ceiling plan, elevations, cross-sections, roof, framing and foundation plans, structural details and calculations, electrical, mechanical and plumbing plans, Title 24 energy forms and, unless waived, a soils report (Building Plan Check Submittal Guidelines; new ADUs including garage conversions are project type E, JADUs type A). Planning issues a clearance, then plans route to Building & Safety, Fire, Planning, Historic Preservation, Riverside Public Utilities (electric and water) and Public Works. Permit-ready route (Dwell Riverside): 1) confirm eligibility on the ADU Express Eligibility Form (single-family lot zoned R-1, RE, RR, RC or RA-5 with an existing or proposed house; not in a flood zone, a Cultural Resources overlay, or a very high fire hazard severity zone under RMC 16.32.365; meets the grading exemption); 2) pick one of four plans and an exterior style; 3) mark the unit's location on a MapRiverside printout as a preliminary site plan; 4) complete the plan cover sheet (T1.1); 5) sign the Hold Harmless Agreement; 6) upload everything to the Permit Portal; 7) after review, download the conditions report and fee estimate, clear conditions at the One Stop Shop, pay fees and pull the permit. Qualifying lots can use the Express submittal, which the city says can reach permit issuance in as few as two One Stop Shop visits. Designated or eligible cultural resources apply for a Certificate of Appropriateness ($0 fee, staff review against the 2025 ADU Design Standards for Historic Properties) first. A permit is valid for 12 months |
| Review Timeline | Permit-ready plans: 3 business days for the first review, 10 for rechecks. Custom ADUs (Tier 2): 20 working days first review, 10 for resubmittals; paid expedited review can halve that. State law: complete applications decided within 60 days (Gov. Code 66317, SB 543). |
| Permit Fees | Valuation-based, not flat: roughly $1,400-$1,500 in Building & Safety permit and plan-check fees for an 800 sq ft ADU on the FY2023-24 schedule ($100.04/sq ft valuation), plus Planning's $289 zoning check and surcharges; the city's 2022 workshop put all-in fees at $3,000-$9,000. |
| Impact Fees | None on an ADU of 750 sq ft or less of interior livable space or a JADU of 500 sq ft or less (Gov. Code 66311.5(c)); RMC 19.442.030(K) mirrors the exemption (its wording omits the 'or less', so a unit at exactly 750 sq ft should cite the state threshold) and charges larger ADUs proportionately to the primary dwelling's floor area. An ADU is not a new residential use for utility connection or capacity charges unless built with a new house, an ADU inside the existing house pays no new connection fee, and a new detached ADU may pay a connection fee or capacity charge proportionate to its size or fixture count (19.442.030(J)). Separate electric, water, gas and sewer connections are optional and cost more (Riverside Public Utilities: 951-826-5489 electric, 951-826-5285 water). School district developer fees can apply to units of 500 sq ft or more |
| Plan Check | Electronic plan check through the Public Permit Portal; each reviewing department posts its conditions in a report you download from the portal, and a plan check expires one year after fees are paid (Plan Check FAQs). Fire sprinklers are not required in an ADU or JADU unless the main house has them; a MADU needs no sprinklers but must be built to ANSI A119.5 or NFPA 1192 (RMC 19.442.030(L)). A MADU must meet the movable-ADU definition in RMC 19.910, be connected to water, sewer and electric, sit on a paved pad with its wheels and hitch screened, keep mechanical equipment off the roof and match the main house's roof pitch and materials (19.442.030(I)-(J)). Fire sprinklers and solar photovoltaics are handled as deferred submittals on the permit-ready plan sets; a two-story custom ADU needs its own structural calculations |
| Pre-Approved Plans | Yes. Dwell Riverside offers four free permit-ready detached single-story ADU plan sets prepared for the city: 746 sq ft (1 bed/1 bath), 800 sq ft (2 bed/2 bath), 1,020 sq ft (2 bed/2 bath) and 1,200 sq ft (3 bed/2 bath), each in Craftsman, Ranch or Spanish exteriors, with foundation options for all soil conditions and optional Very High Fire Hazard Severity Zone and noise-attenuation details. To qualify (ADU Express Eligibility Form, rev. Sept 2024) the lot must be single-family (R-1, RE, RR, RC or RA-5), outside a flood zone, outside the Cultural Resources overlay, outside a very high fire hazard severity zone (RMC 16.32.365) and meet the grading exemption; you sign a hold-harmless agreement and complete the T1.1 cover sheet. Presented to the City Council on December 10, 2024; the city had permitted 835 ADUs and JADUs from 2019 through September 2024 |
Get Free ADU Quotes in Riverside
Tell us about your project and we'll pass it to ADU builders serving Riverside. Free, no obligation — you choose who to work with. We don't have builders in every area yet; if nobody covers yours, we'll email you to say so.
1. Tell us your project
Takes about a minute.
Takes about a minute.
2. We match local pros
Up to 5 independent local ADU builders — never more, and we tell them nothing you don't submit here.
Up to 5 independent local ADU builders — never more, and we tell them nothing you don't submit here.
3. You choose
Compare quotes, verify license & insurance, hire (or don't). No spam either way.
Compare quotes, verify license & insurance, hire (or don't). No spam either way.
🔒 Your info is secure. We share it only with contractors quoting your project. No spam, no obligation.
Just browsing? Search ADU builders near you by ZIP code.
Construction Costs [21][22][23][24][25][26]
Building an ADU in Riverside typically costs $180,000-$320,000 ($180-$280 per sq ft); a garage conversion runs $70,000-$140,000.
See what this means for your lot — ask Riverside ADU builders for a quote →
| Average Build Cost | $180,000-$320,000 |
| Cost per Sq Ft | $180-$280 |
| Garage Conversion | $70,000-$140,000 |
| Prefab ADU (Installed) | $120,000-$250,000 |
Finance Your ADU Project
Most ADU projects are funded through HELOCs, construction loans, or cash-out refinancing. Compare rates from top lenders.
Some links on this page are affiliate links. We may earn a commission at no extra cost to you. Learn more
Rental Income Potential [27][28][29][30]
A 2-bedroom ADU in Riverside rents for around $2,200-$2,400/mo, an estimated About 7-12% gross rental yield on a $180,000-$320,000 detached build at $1,750-$1,950/mo, before taxes, vacancy and financing; a $70,000-$140,000 garage conversion at the same rent returns roughly 15-30% gross.
| Avg Rent (1 Bedroom) | $1,750-$1,950/mo |
| Avg Rent (2 Bedroom) | $2,200-$2,400/mo |
| Short-Term Rental | No. |
| Est. Annual ROI | About 7-12% gross rental yield on a $180,000-$320,000 detached build at $1,750-$1,950/mo, before taxes, vacancy and financing; a $70,000-$140,000 garage conversion at the same rent returns roughly 15-30% gross |
Explore Prefab ADU Options
Prefab ADUs can save 20-40% vs. traditional construction and cut build time in half.
Some links on this page are affiliate links. We may earn a commission at no extra cost to you. Learn more
Recent Law Changes
What's Changed Recently
- Ordinance 7743 (adopted November 4, 2025, effective December 4, 2025) amended RMC 19.442.030 to state that a single-family lot may have one attached or converted ADU, one detached new-construction ADU or MADU, and one JADU, and removed language wrongly suggesting a deed restriction must cap JADU size
- Ordinance 7701 (adopted February 25, 2025, effective March 27, 2025) implemented SB 1211 and HCD direction: up to 8 new detached ADUs on existing multifamily lots and 2 on proposed multifamily lots, attached-ADU size measured against the existing or proposed house, and impact fees charged only at 750 sq ft and above
- Dwell Riverside permit-ready ADU plans (four detached plans, 746-1,200 sq ft) presented to the City Council on December 10, 2024, with a 3-business-day first plan review and an Express Permit-Ready Submittal path for qualifying lots
- Design Standards for ADUs on Historic Properties adopted by the Cultural Heritage Board on February 19, 2025: objective standards applied through the Certificate of Appropriateness review for designated or eligible cultural resources and historic-district lots
- State overlay from January 1, 2026: SB 543 keeps the 60-day deemed-approved deadline and 15-business-day completeness check (Gov. Code 66317); AB 1154 limits JADU owner-occupancy requirements to JADUs that share a bathroom with the main house (Gov. Code 66333(b)); Gov. Code 66311.5 waives impact fees at 750 sq ft or less
Tips for Building an ADU in Riverside
- Check whether your address is inside the City of Riverside or unincorporated Riverside County (MapRiverside or the County's GIS): the County runs a separate ADU program with different standards and fees
- Use a Dwell Riverside permit-ready plan if your lot is zoned R-1, RE, RR, RC or RA-5 and sits outside the flood, very-high-fire-hazard and historic overlays: the design is free, the first plan check takes 3 business days instead of 20, and the Express path can reach a permit in about two One Stop Shop visits
- Keep a new detached unit at one story and 16 ft or under to use the 4-ft side and rear setbacks without question; a 20-ft or two-story ADU is allowed but the city code applies the base zone's setbacks above 16 ft
- Stay at or under 750 sq ft to avoid city impact fees entirely, and under 500 sq ft to avoid school district fees; a 746 sq ft permit-ready plan lands under both thresholds
- Convert the garage: no replacement parking, no added setbacks, no separate size cap, and the city values the work at $21.50 per sq ft for permit fees instead of $100.04 for new construction (FY2023-24 fee handout)
- Stack units on a single-family lot: one attached or converted ADU, one detached new-construction ADU and one JADU are all allowed together since Ordinance 7743
- Historic-district and designated-property owners should budget time for a Certificate of Appropriateness reviewed against the 2025 ADU Design Standards for Historic Properties before the building permit
- Cost basis (2026-09-20 re-verification): avg build cost: $180,000-$320,000 for a new detached ADU of roughly 750-1,000 sq ft in the Inland Empire (CaliFirst Remodel, May 2026: $180,000-$320,000; Dynamic Quality Builders, Feb 2026: $220,000-$350,000 for Riverside County). Attached ADUs run about $160,000-$270,000 (Dynamic Quality Builders). A Dwell Riverside permit-ready plan removes most architectural and engineering fees | cost per sqft: $180-$280 per sq ft for standard finishes and $300-$350 for high-end finishes in the Inland Empire (LA Metro Home Finder, June 2026); Riverside County labor rates run 10-20% below Los Angeles and Orange County (Dynamic Quality Builders, Feb 2026) | garage conversion: $70,000-$140,000 for a full two-car garage conversion (GatherADU, May 2025: $70,000-$115,000; CaliFirst Remodel, May 2026: $75,000-$140,000; Custom Home Design & Build, Feb 2026: $60,000-$120,000 at $150-$240 per sq ft; Dynamic Quality Builders, Feb 2026: $100,000-$160,000). No replacement parking is required | prefab adu: $120,000-$250,000 installed for a 400-1,000 sq ft unit at about $250-$350 per sq ft in Riverside and San Bernardino counties (Autonomous, Feb 2026; GatherADU forum, Oct 2025): the factory unit is $80,000-$180,000, plus site prep $10,000-$30,000, foundation $8,000-$25,000, delivery and crane $5,000-$15,000 and utility hookups $3,000-$15,000. A movable ADU on a chassis (150-430 sq ft) is a separate, smaller category under RMC 19.442 | avg rent 1br: $1,750-$1,950
ADU Builders in Riverside
Looking for an ADU builder in Riverside? ADU projects need a contractor experienced with local zoning, the permit process, and utility connections — not every general contractor has built one. We match Riverside homeowners with experienced local ADU contractors who provide free, no-obligation quotes. Getting at least three bids typically saves 20-40% on the same scope.
Sources & References
All data on this page is sourced from official government records and verified market data. View our full methodology.
- Ordinance No. 7592 (July 2022), Exhibit F: full text of RMC Chapter 19.442 Accessory Dwelling Units (ADU) | City of Riverside Legistar, Case PR-2022-001313 Municipal Code — Accessed 2026-09-20
- Ordinance No. 7701 (adopted Feb. 25, 2025), Section 21 amending RMC 19.442.030 | City of Riverside Legistar, Case PR-2024-001746 Municipal Code — Accessed 2026-09-20
- Ordinance No. 7743 (adopted Nov. 4, 2025), Section 7 amending RMC 19.442.030 and Table 19.150.020.A | City of Riverside Legistar, Case PR-2025-001793 Municipal Code — Accessed 2026-09-20
- City Council Minutes, Nov. 4, 2025 (Ordinance No. 7743 adopted) | City of Riverside Government Data — Accessed 2026-09-20
- Accessory Dwelling Units (ADUs, JADUs and MADUs) FAQs, Planning handout A11 (rev. 9/27/2022) | City of Riverside Planning Division Planning Department — Accessed 2026-09-20
- Generalized Requirements for Single-Family and Multi-Family Residential Zones, Planning handout A8 (rev. 9/22/2022) | City of Riverside Planning Division Planning Department — Accessed 2026-09-20
- RMC Chapter 19.442 (ADU), Municode codification | City of Riverside Code of Ordinances Municipal Code — Accessed 2026-09-20
- Design Standards for Accessory Dwelling Units on Historic Properties (adopted by the Cultural Heritage Board Feb. 19, 2025) | City of Riverside Planning Department — Accessed 2026-09-20
- Permit-Ready ADU Plans: Riverside ADU Permit Process | City of Riverside CEDD Building & Safety building_dept — Accessed 2026-09-20
- Dwell Riverside | City of Riverside CEDD building_dept — Accessed 2026-09-20
- Dwell Riverside: Update on ADU Program including Permit-Ready ADU Plans, City Council memorandum Dec. 10, 2024 | City of Riverside Legistar building_dept — Accessed 2026-09-20
- Building Permit and Plan Check Fees handout (FY2023-24) | City of Riverside Building & Safety Division building_dept — Accessed 2026-09-20
- ADUs and You: Accessory Dwelling Units in Riverside (2022 community workshop) | City of Riverside Planning Department — Accessed 2026-09-20
- Pre-Approved ADU Hold Harmless Agreement and ADU Express Eligibility Form (rev. Sept 2024) | City of Riverside Planning Division Planning Department — Accessed 2026-09-20
- Planning Services Fee Schedule, handout A2 (Resolution 24003, effective July 1, 2023) | City of Riverside Planning Division Planning Department — Accessed 2026-09-20
- Building Plan Review Turnaround Times (2022): ADUs Tier 2, JADUs Tier 1 | City of Riverside Building & Safety building_dept — Accessed 2026-09-20
- Building Plan Check Submittal Guidelines and Plan Submittal Matrix (handout A2) | City of Riverside Building & Safety building_dept — Accessed 2026-09-20
- Plan Check FAQs and Tips (turnaround, expedited review, expiration) | City of Riverside Building & Safety building_dept — Accessed 2026-09-20
- Gov. Code 66317 (ADU review timelines, SB 543) | California Legislative Information Government Data — Accessed 2026-09-20
- Gov. Code 66311.5 (ADU impact fees and utility charges) | California Legislative Information Government Data — Accessed 2026-09-20
- ADU Costs in California (2026): City-by-City Numbers | CaliFirst Remodel (May 28, 2026) industry — Accessed 2026-09-20
- ADU Cost in Southern California: Complete 2026 Pricing Guide by County | Dynamic Quality Builders (Feb. 5, 2026) industry — Accessed 2026-09-20
- ADU Permit Rules: Inland Empire Cities 2026 (cost per sq ft) | LA Metro Home Finder (June 12, 2026) industry — Accessed 2026-09-20
- Garage Conversion Cost California 2026 | Custom Home Design & Build (Feb. 17, 2026) industry — Accessed 2026-09-20
- How much does a Garage Conversion ADU cost in Riverside County? | GatherADU (May 7, 2025) industry — Accessed 2026-09-20
- Prefab ADUs in Southern California: Complete Guide for 2026 | Autonomous (Feb. 26, 2026) industry — Accessed 2026-09-20
- FY 2026 Fair Market Rents, Riverside-San Bernardino-Ontario, CA MSA | HUD User FMR Documentation System Government Data — Accessed 2026-09-20
- Average Rent in Riverside, CA (September 2026) | Zumper Market Data — Accessed 2026-09-20
- Average Rent in Riverside, CA (data as of Aug. 31, 2026) | RentCafe Market Data — Accessed 2026-09-20
- Riverside, CA Rental Market Report (Sept. 2026) | ApartmentAdvisor Market Data — Accessed 2026-09-20
- Gov. Code 66314, 66321, 66323 (state ADU standards: setbacks, height, size, unit counts) | California Legislative Information Government Data — Accessed 2026-09-20
- Gov. Code 66333 (JADU standards, AB 1154 owner-occupancy) | California Legislative Information Government Data — Accessed 2026-09-20
- CA SB 543 (2025-2026): Accessory dwelling units and junior accessory dwelling units | California Legislative Information Government Data — Accessed 2026-09-20
Frequently Asked Questions
Can I build an ADU in Riverside?
Yes. ADUs are allowed in All residential zones and all multifamily and mixed-use zones with an existing or proposed dwelling (RMC 19.442.020). Permitted-use Table 19.150.020.A lists ADUs and JADUs as permitted (P) in the RC, RA-5, RR, RE, R-1, R-3, R-4, MU-N, MU-V and MU-U zones and not in the O, CR, CG, CRC, BMP, I, AI, AIR, PF and RWY zones. JADUs only on lots with a single-family home. Designated or eligible cultural resources and historic-district lots also need a Certificate of Appropriateness under Title 20 and must follow the 2025 ADU Design Standards for Historic Properties; MADUs are barred there in Riverside. The maximum size for a detached ADU is 1,200 sq ft of floor area (RMC 19.442.030(D)(2)). A movable ADU (MADU, a unit on a chassis) must be 150-430 sq ft measured to the outside of the exterior walls (D)(3). Any ADU must be at least the size of an efficiency dwelling unit under California Building Code 1208.4 (D)(5). ADU floor area is not counted toward lot coverage (A)(8). Owner-occupancy is not required, so you can rent out the ADU.
How much does an ADU cost in Riverside?
ADU construction in Riverside typically costs $180,000-$320,000. Garage conversions run $70,000-$140,000, and prefab ADUs cost $120,000-$250,000.
How much can I rent an ADU for in Riverside?
Average ADU rents in Riverside are $1,750-$1,950/mo for a 1-bedroom and $2,200-$2,400/mo for a 2-bedroom unit.
Do I need parking for an ADU in Riverside?
None. No parking space is required for an ADU, MADU or JADU, and no replacement parking is required for the main house when a garage, carport or covered parking is converted to an ADU (RMC 19.442.030(H)). Check with Riverside planning department for the latest California ADU parking rules, as many states have relaxed requirements in recent years.
How long does it take to get an ADU permit in Riverside?
The permit review timeline in Riverside is Permit-ready plans: 3 business days for the first review, 10 for rechecks. Custom ADUs (Tier 2): 20 working days first review, 10 for resubmittals; paid expedited review can halve that. State law: complete applications decided within 60 days (Gov. Code 66317, SB 543).. Permit fees: Valuation-based, not flat: roughly $1,400-$1,500 in Building & Safety permit and plan-check fees for an 800 sq ft ADU on the FY2023-24 schedule ($100.04/sq ft valuation), plus Planning's $289 zoning check and surcharges; the city's 2022 workshop put all-in fees at $3,000-$9,000.
Ready to Build in Riverside?
Get free, no-obligation quotes from top-rated ADU contractors in Riverside.
Get Free Quotes →Build ADUs in Riverside?
Homeowners read this page while planning, then ask us to connect them with a local builder. We pass those requests to builders who cover Riverside — a flat fee only on the leads you accept, no subscription, and you contract directly with the homeowner.
See who's waiting in California →