ADU Constructionin Chino, CA
ADU construction in Chino follows state law first: approval is ministerial, the City must check completeness in 15 business days and decide within 60, and a detached unit of 800 square feet needs only 4 foot setbacks. Chino's table allows 1,200 square feet, and the Fire District must issue its permit before the City issues the building permit.
Chino was a farm town long before it was a suburb. The Rancho Santa Ana del Chino grant dates to 1841, Richard Gird subdivided the rancho into small ranches and a town site in 1887, the city incorporated in 1910, and dairy herds moved in from Los Angeles and Orange counties from 1950. The Census Bureau's 2020 to 2024 estimate counts 28,188 homes, with a margin of error of plus or minus 624, and 67.6 percent are single-family detached, the lot type backyard units are written for. The median owner-occupied home is worth $683,400, plus or minus $15,367, and the median year built is 1987.
This page leads with state law, then reads the City's rules against it: the size table, garage conversions, pre-approved plans, the Chino Valley Independent Fire District, former dairy land, our fire-zone overlay and the fees. The City's own site answered our requests, but the official code copy on Municode returned a Cloudflare block that we did not work around, so the Municipal Code wording comes from GoCodebook, a third-party mirror. Confirm each point with Planning at 909-334-3253 or the Building Division at 909-334-3251. Prices and phases are on our ADU construction page.
City of Chino rules that apply to ADU construction
Where adu construction permits come from in Chino: City of Chino Development Services Department, Building Division.
- ADU rules are in Municipal Code 20.11.020 (accessory dwelling units and junior ADUs, written to Government Code 65852.2 and 65852.22): one ADU plus one JADU per lot with a single-family home; on multifamily lots either ADUs equal to 25 percent of the units (minimum one) inside non-livable space, or up to two detached ADUs; a JADU is at most 500 square feet inside or attached to the home, needs a separate entrance and may share a bathroom.
- ADU size and setbacks (Table 20.11-2): attached or inside the primary dwelling, 50 percent of the existing primary dwelling or 1,200 square feet, whichever is less (JADU 50 percent or 500 square feet); detached up to 1,200 square feet and no more than 80 percent of the primary structure's floor area excluding garages, but always allowed up to 800 square feet; front and street side setbacks same as the main building and 4 feet interior side and rear for new construction (none for converting an existing structure without changing its dimensions); one story and up to 16 feet; no minimum lot size.
- An ADU may be built on top of a one-story detached garage or other detached structure only in the RD 8, RD 12, RD 14, RD 20 and mixed use districts, and not in RD 1, RD 2, RD 4.5 or AG (note [4] to Table 20.11-2); architecture, roof material and exterior colors must match the primary dwelling; sprinklers are not required unless the primary home needs them; ADUs cannot be sold apart from the home and cannot be rented for fewer than 31 consecutive days.
- ADU parking: one covered or uncovered space per ADU (20.11.020, Table 20.18-1), but none when the ADU is within a half mile walking distance of public transit, in a historic district, entirely inside the existing home or accessory structure, or where on-street permit parking is not offered to the occupant.
- The City's ADU page offers preapproved detached ADU plans (studio, 1, 2 and 3 bedroom) and lets private-vendor preapproved plans in; a preapproved plan still needs submittal, plan check and approval, only faster, and owners sign a hold-harmless statement releasing the City and the plan architect. JADUs may be built only inside the footprint of the existing primary dwelling or attached garage, not in a detached structure. Property eligibility questions go to Planning at 909-334-3253.
- ADU fire review: the Chino Valley Fire District charges $452 for an ADU plan review that covers plan review, permit and inspection, with a 7 to 10 business day review time; plans must be electronic PDFs with a CVFD plan check application and a fire flow report from the water provider (City of Chino Public Works Engineering 909-334-3265, Chino Hills Public Works or Monte Vista Water District), and the City will not issue a building permit before the District issues its permit.
- Second primary units and duplexes in single-family zones (Municipal Code 20.04.050, Government Code 65852.21) are allowed only in RD 1, RD 2 and RD 4.5, are reviewed through zoning clearance with a courtesy notice mailed to adjacent owners at least ten days before a decision, and are barred on parcels such as prime farmland, wetlands, very high fire hazard severity zones (unless mitigated) and delineated earthquake fault zones.
- ADU conversions of a garage are exempt from the garage replacement parking rule, while a non-ADU garage conversion is not: when a house without off-street parking is enlarged by more than 5 percent of its floor area or its attached garage becomes habitable space (other than an ADU or JADU), Municipal Code 20.18.040 requires one covered space for homes built on or before May 20, 1965 and two covered garage spaces for homes built after.
Build an ADU in Chino: does state law or the City's code decide?
State law decides wherever the two differ, and on the basics they agree. Government Code Section 66317 says an ADU permit is considered and approved ministerially, without a hearing or discretionary review. Since January 1, 2026, the City has 15 business days to tell you in writing whether your application is complete and 60 days after a complete application to approve or deny it when a house already stands on the lot, and silence for those 60 days counts as approval. Section 66314 limits the City to objective standards, bars any minimum lot size and caps side and rear setbacks for new construction at 4 feet.
Chino's Section 20.11.020 is written to those statutes: one ADU plus one junior ADU on a lot with a single-family home, and on a multifamily lot either ADUs equal to 25 percent of the units or up to two detached ADUs. State law also protects four types a city must approve, including an ADU and a JADU converted inside the existing home, and one new detached ADU up to 800 square feet with 4-foot setbacks. Read the statute chapter and HCD's ADU handbook if a counter answer sounds stricter than that.
Statute sections are as renumbered by SB 543 on January 1, 2026. Chino's code wording comes from GoCodebook's mirror, last updated October 4, 2026.
How big can a Chino ADU be, and how many units fit on one lot?
Table 20.11-2 sets the sizes. An ADU attached to or inside the home can be 50 percent of the existing primary dwelling or 1,200 square feet, whichever is less, and a junior ADU tops out at 500 square feet and must sit inside the existing footprint of the home or its attached garage. A detached ADU can reach 1,200 square feet but no more than 80 percent of the primary structure's floor area, excluding garages, and the table always allows up to 800 square feet. Detached units are one story and up to 16 feet tall.
Front and street side setbacks match the main building, and new construction needs 4 feet at the interior side and rear, with no setback when you convert an existing structure without changing its dimensions. Our reading of the state text puts the floor for a local size cap at 850 square feet, or 1,000 with more than one bedroom, so if the 80 percent rule leaves your lot below that, ask Planning how the City applies it. An ADU cannot be sold apart from the house, and the table bars rentals shorter than 31 consecutive days.
Can you convert a Chino garage into an ADU, build over one, and skip the replacement parking?
Yes to the conversion, and the parking need not be replaced. Section 20.18.040 exempts a garage turned into an ADU or JADU from the City's garage replacement rule, and state law agrees: Sections 66314 and 66322 bar replacement parking when a garage, carport or covered structure is converted or demolished for an ADU. A converted structure keeps its existing setbacks if its dimensions do not change, and the state allows up to 150 square feet of added space for entry and exit when an ADU and JADU go inside an existing structure.
The ADU itself needs one space, covered or not, but none when it is within a half mile walking distance of public transit, entirely inside the existing home or an accessory structure, in a historic district, or where on-street permit parking is not offered to the occupant. Two traps remain. A garage turned into ordinary living space, not an ADU, still triggers replacement parking: one covered space for homes built on or before May 20, 1965 and two garage spaces for later ones. And a unit on top of a one-story detached garage is allowed only in RD 8, RD 12, RD 14, RD 20 and the mixed use districts, not in RD 1, RD 2, RD 4.5 or agricultural zones.
Does Chino have pre-approved ADU plans, and why does the Fire District come first?
The City's ADU page offers pre-approved detached ADU plans in studio, one, two and three bedroom layouts and accepts pre-approved plans from private vendors. A pre-approved plan still goes through submittal, plan check and approval, only faster, and the owner signs a hold-harmless statement releasing the City and the plan's architect. We did not read the plan sizes, so check each layout against the size table and your setbacks before you pick one. Questions about whether a property is eligible go to Planning.
Fire review runs through the Chino Valley Independent Fire District, not the City. Its ADU guideline charges $452 for a review that covers plan check, permit and inspection, quotes 7 to 10 business days, and asks for electronic PDFs, the District's plan check application and a fire flow report from the water provider: City of Chino Public Works Engineering at 909-334-3265, Chino Hills Public Works or Monte Vista Water District. The City will not issue the building permit until the District issues its own, so start that file early and get the water provider's report on the calendar.
Was your Chino lot a dairy, and what does the methane handout mean for an ADU slab?
A lot's past can show up in the paperwork here. The EPA's Santa Ana Region summary says the Chino Basin once held about 350 dairies and over 300,000 cows across 20 square miles, and that dairies fell to 86 by 2015. A 2000 University of California farm advisor paper had already flagged residual methane in the soils of vacated dairies as a concern for home buyers. The City's methane handout answers with a process, starting with a Phase 1 report on whether a site was ever a dairy, poultry or hog ranch, manure stockpile, burial site or agricultural pond.
Where testing is needed, the handout sets mitigation by the reading: a moisture barrier at least 10 mil thick with sealed utility penetrations under 15,000 ppm, and special remediation above that or at burial sites, ponds and lowlands, with a soils report that limits organics to 2 percent. The Building Division must approve the reports and mitigation before a permit issues. We did not find whether the City asks for this on one backyard ADU on an older lot, and the handout is undated, so ask the Building Division before you pay for a slab design.
Is a Chino lot in a fire hazard zone, and does the Prado Basin flood map matter for an ADU?
Only a small part of the city is mapped, and it is not where most homes are. CAL FIRE gave the Chino Valley Independent Fire District its recommended zones on March 24, 2025, and the District adopted them unchanged in Ordinance 2025-01, effective September 1, 2025. The District's map viewer could not be read by our tools, so we laid CAL FIRE's State layer over the Census boundary of Chino ourselves. It is our own overlay, not an official City map: about 2.00 square miles Very High, 0.29 High and 0.50 Moderate out of 30.0, with about 3.1 square miles the layer does not cover.
All of the mapped acres sit in a southern strip on the Prado Basin side, between roughly 33.924 and 33.962 N and 117.611 and 117.677 W. City Hall, downtown, Ruben S. Ayala Park, College Park, Chino Airport and The Preserve test as not wildland, while the Yorba-Slaughter Adobe point tests Very High. Look up a parcel on the District's hazard map page. The Housing Element also puts the southwest in the 100-year floodplain and the area south of Pine Avenue inside the Army Corps' Prado Flood Control Basin, and in a special flood hazard area the lowest floor of new construction must be at least one foot above base flood elevation (Section 8.60.190).
What do ADU fees, utilities and the rental rules add in Chino, and how long does it take?
State law caps impact fees: none on an ADU of 750 square feet or less, and none on a junior ADU of 500 or less. Utility connection charges sit outside that exemption, and an ADU converted from existing space cannot be forced into a new utility connection. The City's schedule, effective July 1, 2026, charges building permits by valuation, plan check at 75 percent of the permit fee, $67.94 to issue each electrical, plumbing or mechanical permit, and a residential school fee of $5.38 per square foot that the Chino Valley Unified School District collects before permit issuance. State law treats a unit under 500 square feet as adding no assessable school space, so ask which fees reach yours.
Sprinklers are not required in an ADU unless the main home needs them, and an ADU cannot trigger sprinklers in the main house. HCD's handbook says a new detached ADU must carry solar panels under the Energy Code, while conversions need not. Section 15.45.060 applies a 10 percent energy set-aside to residential additions and alterations valued at $65,000 or more, so ask whether an attached unit or large conversion counts. Work runs 7:00 a.m. to 8:00 p.m. Monday through Saturday.
MDG Builders, CSLB #1040337, is the general contractor on an ADU: it designs the package, pulls the permits and schedules the trades, and licensed subcontractors pour, frame, wire and plumb the unit.
ADU photos from Chino and nearby homes
ADU scenes tied to Chino, from garage conversions and backyard cottages to slab framing and utility trenches, on lots from the old ranch town to the 1970s and newer tracts. Tap a photo to enlarge it.
What adu construction costs around Chino
Our ADU construction page plans a garage conversion to a studio or one bedroom near $100,000 to $200,000 and a new detached unit of 400 to 800 square feet near $200,000 to $400,000. Three studies sit behind the ranges. UC Berkeley's survey of owners who built or applied in 2018 and 2019 found a Los Angeles County median of $100,000, the Terner Center estimated $148,000 for Los Angeles in 2020, and the 2025 edition of Remodeling magazine's Cost vs. Value report lists a Los Angeles ADU job at $178,536, of which resale recovers 39.9 percent. None is a Chino bid, so San Bernardino County costs can differ. A methane barrier, a long sewer or water run, a fire flow report, a utility upgrade or a flood-zone floor height can each add a line, and the City's and District's fees belong on their own lines in a written proposal. Our ADU cost guide explains how the ranges were built, and the ADU versus JADU guide covers the junior unit. ADUs in nearby cities are on our Ontario, Pomona, Eastvale and Norco pages. A bath inside the unit is on the Chino bathroom page, an attached project on the Chino room addition page, windows on the Chino window page, and the Chino area page lists every trade we cover in the city.
| What it covers | Typical range |
|---|---|
| Garage conversion to a studio or one bedroom | $100,000 to $200,000 |
| New detached ADU, 400 to 800 sq ft | $200,000 to $400,000 |
| UC Berkeley survey, Los Angeles County median, 2018 and 2019 projects | $100,000 overall. $90,000 garage. $180,000 detached. |
| Terner Center and Berkeley CCI, 2020 | $148,000 Los Angeles estimate. $167,000 statewide average. |
| Remodeling Cost vs. Value 2025, Los Angeles | $178,536 job cost |
| Electrical and plumbing, Angi Los Angeles, January 2026 | Electrical $2,600 to $7,800. plumbing $3,900 to $10,400. |
| City permit and plan check fees | Not priced here |
Chino ADU questions, answered
How do I build an ADU in Chino?
Start with state law and Chino's Section 20.11.020, pick a type (garage conversion, attached or detached), then submit plans to the Building Division and to the Chino Valley Independent Fire District, which must issue its permit first. The City has 15 business days to check completeness and 60 days to decide. Planning at 909-334-3253 answers lot eligibility questions.
How big can an ADU be in Chino?
A detached ADU can reach 1,200 square feet but no more than 80 percent of the primary structure's floor area, excluding garages, and 800 square feet is always allowed. An attached or interior unit is limited to 50 percent of the existing home or 1,200 square feet, whichever is less. A junior ADU is capped at 500 square feet.
How much does it cost to build an ADU in California?
Our planning range for converting a garage to a studio or one bedroom is $100,000 to $200,000, and for a new detached unit of 400 to 800 square feet it is $200,000 to $400,000. Both come from Berkeley, Terner Center and Cost vs. Value studies of Los Angeles, not Chino bids, so only a site visit and a written proposal set a price.
Do I need to provide parking for my ADU?
Usually not for a garage conversion: Chino exempts converted garages from replacement parking, and state law agrees. A new ADU needs one space, except within a half mile walking distance of public transit, inside the existing home or accessory structure, in a historic district, or where on-street permit parking is not offered to the occupant.
What is the difference between an ADU and a JADU?
A junior ADU is capped at 500 square feet and must sit inside the existing footprint of the home or its attached garage, with a separate entrance, while an ADU can be larger and detached. Chino allows one ADU and one JADU on a single-family lot, and a JADU may share a bathroom with the main home.
Do I have to live on the property to build or rent an ADU?
Not for an ADU: state law does not let a city require owner occupancy for one, though a city may require rentals of 30 days or longer, and Chino bars rentals under 31 days. A junior ADU needs an owner on site only if it shares a bathroom with the main home.
How long does it take to get an ADU permit?
State law gives the City 15 business days to check completeness and 60 days to decide a complete application, and an application left without action for 60 days is deemed approved. The Fire District quotes 7 to 10 business days for its own review. Drawings, corrections and construction come on top of the permit clock.
Can I convert my unpermitted garage into a legal ADU?
Possibly. Under Government Code Section 66311.7, a city cannot deny a permit for an unpermitted ADU built before January 1, 2020 over code violations unless correction is needed for health and safety under Health and Safety Code Section 17920.3. Ask Planning how Chino handles it, and expect a records search and an inspection.
Does Chino have pre-approved ADU plans I can use?
Yes. The City offers pre-approved detached plans in studio, one, two and three bedroom layouts and accepts plans from private vendors, but each still goes through submittal, plan check and approval, and the owner signs a hold-harmless statement. Check the plan against your lot's setbacks and the City's size table first.
Tell us about your Chino ADU plans
Tell us the tract or street, whether you are weighing the garage or the back yard, whether the lot was ever a dairy or farm, and whether it sits near the Prado Basin, and the first visit will start from the state clocks, the Fire District file and the methane question.