Chino | ADUs and SB 9
Chino, California ADUs and SB 9: Chapter 20.503, ADU Sizes, Heights, Setbacks, Parking, Junior ADUs and Second Primary Units
This page covers the two state routes to a second or third home on a Chino house lot. An accessory dwelling unit, or ADU, is a second home on a lot with a main home; a junior ADU, or JADU, is a unit of up to 500 square feet inside or attached to a house. SB 9 lets an owner build two main homes on a single-family lot. Chino's 2026 zoning code puts its ADU rules in Chapter 20.503 and its SB 9 rules in Section 20.201.050. Both chapters say they carry out state law, and several City rules are stricter than today's statutes. This page sets the City text beside state law and says which controls. The Chino overview has the summary.
Chino ADUs and SB 9 in six facts
- A detached ADU may have up to 1,600 square feet in RD 1 and RD 2 and up to 1,200 square feet in other zones. Source: Chino Zoning Ordinance, Table 20.503-1
- A detached ADU may be one story and 16 feet tall, or 18 feet within one-half mile walking distance of a major transit stop or high-quality transit corridor. Source: Chino Zoning Ordinance, Table 20.503-1
- A new ADU needs four-foot side and rear setbacks, and no setback is needed to convert an existing structure of the same size. Source: Chino Zoning Ordinance, Table 20.503-1, note 3
- The City must approve or deny a complete ADU application within 60 days, or 30 days for a pre-approved plan, or it is deemed approved. Source: Chino Zoning Ordinance 20.503.030(A)(3)
- An SB 9 second primary unit in Chino may have no more than 800 square feet and one story of 16 feet, with four-foot side and rear setbacks. Source: Chino Zoning Ordinance 20.201.050(E)
- State law lets a city ask for no more than one parking space per ADU or per bedroom, whichever is less. Source: Government Code 66314(d)(10)
How Many ADUs a Chino Lot May Hold
Section 20.503.010 says the chapter "is intended to implement the provisions of Sections 66310 through 66342 of the Government Code and, in case of ambiguity, shall be interpreted to be consistent with such provisions." ADUs are a permitted use in every residential district, and junior ADUs in RD 1 to RD 12. On a lot with a house, Section 20.503.020(A)(2) allows "No more than one accessory dwelling unit and one junior accessory dwelling unit." That is three homes on one lot: the house, the ADU and the junior ADU.
On a lot with an apartment building there are three options. Converted ADUs may fill space in the building "not used as livable space", such as storage rooms, attics, basements or garages, up to 25 percent of the units, rounded down, with at least one. The code's own example: one ADU in a building of seven or fewer units, two in a building of eight to eleven, three in a building of twelve. A lot with an existing apartment building may also have "No more than eight detached accessory dwelling units", never more than the existing units, and a lot with a proposed apartment building may have two detached ADUs. On a lot created by an SB 9 urban lot split, Section 19.04.110 limits the lot to two units in total, counting ADUs.
An ADU needs a kitchen and a full bathroom. A junior ADU needs an efficiency kitchen and may share the house's bathroom. An ADU or junior ADU inside or attached to a house needs its own entrance, but "no passageway to the unit is required." A manufactured home or an efficiency unit, as defined in Health and Safety Code 17958.1, may serve as an ADU.
Size, Height and Setbacks
| Feature | Rule in Table 20.503-1 |
|---|---|
| Attached ADU, size | 50 percent of the existing house, or 1,600 sq ft in RD 1 and RD 2 and 1,200 sq ft in other zones |
| Junior ADU, size | 500 sq ft, inside or attached to a single-family home |
| Detached ADU, size | 1,600 sq ft in RD 1 and RD 2; 1,200 sq ft in other zones |
| Front and street side setback | Same as the main building |
| Interior side and rear setback | 4 ft; none for a conversion that keeps the same dimensions |
| Height, detached | 1 story and 16 ft; 18 ft near a major transit stop or high-quality transit corridor, plus 2 ft to match the roof pitch of the house |
| Height, attached | Two stories and 25 ft, or the height limit of the house if lower |
| Height, in or on a multifamily structure | 18 ft |
| Above a detached garage | Allowed in RD 8, RD 12, RD 14, RD 20 and mixed use zones; not in RD 1, RD 2, RD 4.5 or AG |
| Minimum lot size | None |
Source: Chino Zoning Ordinance Table 20.503-1 and its notes 1 to 4 (August 2026).
The size caps "apply to the entire structure, including a garage, exterior storage space, or other structure that is attached to the unit but is not intended for use as livable space." Setbacks are the open distances a building must keep from the lot lines; they "only apply to construction of new buildings", so a garage or room converted to an ADU without changing its size needs none. When an ADU is made from an existing accessory structure, "up to 150 square feet may be added" for an entrance.
Other rules of the main home apply, including lot coverage, the share of the lot covered by buildings. Section 20.503.020(B)(1)(a) raises the coverage limit in RD 1 and RD 2 to 30 percent for this purpose, which Table 20.201-3 now sets for all buildings in those two districts, and Section 20.503.020(B)(1)(c) says that when coverage or floor area rules "would prevent the approval of an attached or detached accessory dwelling unit that is at least 800 square feet", the owner may still build one of up to 800 square feet. Design, roof and colors must match the objective standards for the house. Fire sprinklers are needed only when the Building Code needs them in the house.
How a Chino ADU Is Approved
Section 20.503.030 sets two routes. Four kinds of ADU need only a building permit: an ADU or junior ADU made inside a house; one new detached ADU on a house lot with four-foot side and rear setbacks, 800 square feet or less and within the height limit; converted ADUs inside an existing apartment building; and detached ADUs on an apartment lot within the numbers above. Every other ADU needs a building permit plus "the Director's ministerial approval", a staff check against written rules through the zoning clearance in Section 20.603.090, with no hearing.
"The City must approve or deny an application to create an ADU or JADU within 60 days from the date that the City receives a completed application or 30 days if the application is for a pre-approved ADU plan." If it does not, the application is deemed approved, unless the applicant asks for a delay or the ADU is filed with a new house, which the City may decide first. A denial must list "all the defective or deficient items" and how to fix them. Government Code 66317 adds that the City must say whether the application is complete "not later than 15 business days after the permitting agency received the application."
Section 20.503.030(B) describes the City's pre-approved ADU plan program: plan sets that the Planning Commission approves and the City posts on its website, so an owner can add site details and file. The City also issues the demolition permit for a garage being replaced by an ADU together with the ADU permit, with no posted notice unless the lot is in a historic district. It may not deny an ADU for a nonconforming zoning condition or an unpermitted structure that is not a health or safety threat, and it may give up to five years to fix such a problem. An ADU that does not meet the standards can ask for a variance, which is a discretionary exception decided by the Director or the Planning Commission.
The City Rules Beside State Law
| Subject | Chino 2026 code | State law (Government Code section) |
|---|---|---|
| ADU parking | One space per ADU bedroom (Section 20.503.020(B)(3)); one space per dwelling (Table 20.511-1) | No more than one per ADU or per bedroom, whichever is less (66314) |
| Junior ADU owner occupancy | Owner must live in the house in every case | Required only if the junior ADU shares sanitation facilities (66333) |
| Impact fee waiver | ADUs and junior ADUs "less than 750 square feet" | No impact fee on an ADU of 750 sq ft of interior livable space or less (66311.5) |
| Above a detached garage | Section 20.503.020(A)(1) allows it; Table 20.503-1 note 4 bars it in RD 1, RD 2, RD 4.5 and AG | A detached ADU may be in a detached garage (66314(d)(3)) |
| Detached ADUs, existing apartments | Up to eight, no more than the existing units | Up to eight, no more than the existing units (66323) |
| Review time | 60 days; 30 days for a pre-approved plan | 60 days; completeness notice within 15 business days (66317) |
Sources: Chino Zoning Ordinance Chapter 20.503 and Table 20.511-1; Government Code 66311.5, 66314, 66317, 66323 and 66333.
Parking. Section 20.503.020(B)(3) says "One on-site parking space shall be provided for each accessory dwelling unit bedroom." The parking table in Chapter 20.511 says "1 covered or uncovered space per dwelling" for an ADU. Government Code 66314(d)(10) says parking "shall not exceed one parking space per accessory dwelling unit or per bedroom, whichever is less." The statute controls, so a two-bedroom ADU needs at most one space. No space is needed within one-half mile walking distance of public transit, in a historic district, for an ADU inside the house or an accessory structure, where on-street permits are not offered to the ADU, within one block of a car share vehicle, or in some cases when the ADU is filed together with a new home. A garage converted or torn down for an ADU need not be replaced.
Junior ADU owner occupancy. Section 20.503.020(B)(6) says "The property owner must reside in any single-family residence that includes a junior accessory dwelling unit." Government Code 66333(b), as amended by AB 1154 effective January 1, 2026, says "Owner-occupancy shall not be required if the junior accessory dwelling unit has separate sanitation facilities." The statute controls. Confirm the deed restriction wording with the City before recording it.
Fees. Section 20.503.030(D) waives City, special district and water impact fees for ADUs "that are less than 750 square feet", and school fees under 500 square feet. Government Code 66311.5 sets the line at "750 square feet of interior livable space or less", so an ADU of exactly 750 square feet pays no impact fee under the statute. Larger ADUs pay in proportion to the house under the statute; the City's Fiscal Year 2025-26 impact fee schedule lists a total of $8.20 per square foot for ADUs of 751 to 1,200 square feet.
Rentals. An ADU or junior ADU may not be sold apart from the house. Section 20.503.020(B)(2)(b) lets it be rented separately "if the owner has a business license unless the City Manager has granted an exemption", for terms of at least 31 consecutive days.
SB 9 Second Primary Units and Duplexes
Section 20.201.050 sets "procedures and standards for the approval and creation of second primary units and duplexes in single-family zones in accordance with the requirements of Government Code Section 65852.21." A second primary unit is a second main home on the lot, attached or detached. The City reviews it through a zoning clearance, mails a courtesy notice to the owners next door at least ten days before deciding, and "shall approve" an application that meets the section. Appeals follow the City's appeal rules.
| Subject | Chino Section 20.201.050 | Government Code 65852.21 |
|---|---|---|
| Zones | RD 1, RD 2, RD 4.5 and RD 8 | A single-family residential zone |
| Size of the second unit | No larger than 800 sq ft | Standards may not keep either unit under 800 sq ft, and must apply uniformly in the zone |
| Height of the second unit | One story and 16 ft, never above another structure | No height rule of its own; standards must apply uniformly in the zone |
| Side and rear setbacks | 4 ft; none for an existing structure rebuilt in place | Up to 4 ft; none for an existing structure |
| Parking | One space per unit (Section 20.201.050(F)); one per bedroom (Table 20.511-1) | Up to one space per unit; none near transit or car share |
| Denial | Adverse impact on "public health and safety or the physical environment" | Adverse impact on "public health and safety" |
| Decision time | Zoning clearance; neighbors notified 10 days ahead | 60 days from a complete application, or deemed approved |
| Rentals | No term under 31 days | Term longer than 30 days |
Sources: Chino Zoning Ordinance Section 20.201.050 and Table 20.511-1; Government Code 65852.21, as amended by SB 1426 effective June 30, 2026.
The City's size and height caps are the main conflict. Section 20.201.050(E) says second primary units "shall be no larger than eight hundred square feet in floor area" and "no taller than one story and 16-feet in height", and the same applies to at least one unit of a new attached duplex. Those caps apply only to SB 9 units; a house in RD 4.5 may be two and a half stories and 35 feet. Government Code 65852.21(b)(3) says a local agency "shall not impose objective zoning standards, objective subdivision standards, and objective design standards that do not apply uniformly to development within the underlying zone." The statute controls, so an owner may ask the City to apply the same size and height rules it applies to a house. Get the answer in writing.
The section keeps the state protections. The project may not remove rent-restricted or rent-controlled housing, or housing "occupied by a tenant in the last three years", or sit on land withdrawn from rent under the Ellis Act within 15 years. Each unit needs its own entrance and its own utility connections, and the City Engineer checks utility capacity before the building permit. The owner records a deed restriction, and the units may not become condominiums or be sold apart. Section 20.201.050(H) says the City "shall not enforce any zoning, subdivision, or design standard to the extent that it would have the effect of physically precluding the construction of up to two primary residential units on a parcel."
SB 9 two-unit projects and SB 9 lot splits can be combined. With a split, each new lot may hold two units in total, so the original lot reaches four homes. Without a split, VanPlex reads the code to let the house, an SB 9 second unit, an ADU and a junior ADU share one lot, since Section 20.201.050(I) counts "primary dwelling units" as homes other than ADUs; confirm this with the City. State law says a city need not allow ADUs on lots that use both SB 9 sections. The lot size and subdivisions page covers the split.
Best For
- ✓ RD 1 and RD 2 lots, where a detached ADU may reach 1,600 square feet.
- ✓ House lots where a garage or spare room can become an ADU with only a building permit and no setback.
- ✓ Owners near a major transit stop or high-quality transit corridor, where a detached ADU may be 18 feet tall and needs no parking.
Usually Fails When
- ✕ An SB 9 second unit is drawn larger than 800 square feet or taller than one story without first asking the City about Government Code 65852.21(b)(3).
- ✕ A plan counts on an ADU above a detached garage in RD 1, RD 2 or RD 4.5.
- ✕ A budget assumes an ADU of 751 square feet or more pays no impact fee.
What To Verify Before Spending Money
- → Whether the City asks one parking space per ADU or per bedroom.
- → Whether the City still records owner occupancy on a junior ADU with its own bathroom.
- → Whether a pre-approved ADU plan fits the lot, for the 30-day review.
Where to Go Next
Related on VanPlex: the Chino overview, the California ADU law page and the California SB 9 page.
Frequently Asked Questions
How big can an ADU be in Chino, California?
How tall can a detached ADU be in Chino?
Can I build an ADU above my garage in Chino?
How many ADUs can I add to a Chino house lot?
Does a Chino ADU need a parking space?
Do I have to live in the house to add a junior ADU in Chino?
How long does Chino take to approve an ADU?
Are there impact fees on an ADU in Chino?
Can I build two homes on my Chino lot under SB 9?
Can I sell an SB 9 unit or ADU separately in Chino?
Official sources (checked October 2026)
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