Riverside | Zoning Districts

Riverside Zoning Districts: RA-5, RC, RR, RE, R-1, R-3 and R-4

A zone is the label the City puts on each lot to say what may be built there and how big it may be. Riverside's residential zones are in Chapter 19.100 of the Riverside Municipal Code, the Zoning Code that sits in Title 19. This page lists each zone, how many homes it allows, and the overlays that add rules on top. It reads Supplement 33 of the code, which includes ordinances through No. 7776 of June 23, 2026. The Riverside overview sums up the whole guide.

The Residential Zones and What Each Is For

Section 19.100.010 says the zones exist "to implement the residential land use designations of the General Plan," the City's long-range land plan. Each zone has a written purpose, and the purpose explains who the zone was drawn for:

• RA-5, Residential Agricultural. Farming "independently or in conjunction with a single-family residence," on lots of 5 acres.
• RC, Residential Conservation. Set up "consistent with General Plan objectives and voter approved initiatives (Proposition R and Measure C)" to protect ridges, hillsides, slopes, arroyos and canyons. An arroyo is a steep-sided natural drainage channel. The hillsides and historic districts page covers this zone in detail.
• RR, Rural Residential. Single-family homes on large lots where owners may keep horses, cows, goats and other farm animals, including animals in Future Farmers of America and 4-H projects.
• RE and R-1-1/2 Acre. Large-lot single-family homes "where the keeping of livestock and other farm animals and agricultural uses are not permitted."
• R-1-13000, R-1-10500, R-1-8500 and R-1-7000. Single-family homes "with a variety of lot sizes and housing choices." The number is the smallest lot in square feet.
• R-3-4000 to R-3-1500. Multiple-family homes, "including such residential development types as apartments, town homes, condominiums," tiny homes on foundations, and small-lot single-family subdivisions.
• R-4, Very High-Density Residential. Higher density apartments "in areas of the City readily served by public transit and near commercial zones."

The code counts its own zones two ways. Section 19.100.010 says "Fourteen residential zones are established," while the title of Chapter 19.100 lists fifteen: RA-5, RC, RR, RE, R-1-1/2 Acre, four more R-1 zones, five R-3 zones and R-4. The tables that follow give standards for all fifteen.

Single-Family Zones: Density, Lot Size and Height

Density is the number of homes allowed per acre of land. Riverside measures it per gross acre, which note 1 to Table 19.100.040 A defines this way: "Gross acreage means streets are included for density purposes." Each lot must still meet the minimum lot size "exclusive of streets."

Source: Riverside Municipal Code Table 19.100.040 A, Supplement 33.

Lot coverage is the share of the lot that buildings may cover. It runs from 30 percent in the large-lot zones to 40 percent in R-1-7000. Section 19.442.030 keeps ADUs out of that count: "The floor area of an ADU, MADU or JADU shall not be counted when calculating lot coverage." The height of 35 feet and two stories is the same in every R-1 zone, RR, RE and RA-5. RC is the exception at 20 feet and one story.

Older small lots have their own rules. Section 19.100.065 sets standards for legally created R-1 lots under 5,500 square feet, with three stories and lot coverage up to 55 percent on the smallest lots. Larger lots that fall short of their zone's minimum borrow the standards of the R-1 zone that fits their size. The lots and subdivisions page has those tables.

Multiple-Family Zones: R-3 and R-4

Table 19.100.040 B sets the density for the six multiple-family zones. In R-3 the second number in the zone name tracks the land per home, and the density rises as that number falls.

Source: Riverside Municipal Code Table 19.100.040 B and its note 2.

Every R-3 and R-4 zone lists a minimum lot area of 30,000 square feet, a minimum width of 80 feet (100 feet in R-4), and a minimum depth of 100 or 150 feet. Many existing R-3 lots are smaller. Section 19.100.075 covers them: it applies "to residential infill development projects in the R-3 and R-4 zones on lots less than 21,780 square feet in area," and replaces the table above with smaller setbacks and a 40-foot height. Infill means new building on a lot inside an area that is already built up. The three or more homes page goes through those small-lot rules.

R-3 and R-4 also carry open space, design and parking rules in Section 19.100.070. Each home needs common open space shared by residents (400 square feet per home in R-3-4000, down to 150 in R-4) and private open space such as a patio or balcony. All new R-3 and R-4 buildings need design review under Section 19.100.080. Design review is the City's check of a building's look and layout before a building permit.

What Each Zone Allows

Table 19.150.020 A is the City's use table. A "P" means permitted, an "X" means prohibited, and "PRD" means the use needs a Planned Residential Development permit, a permit for a group of homes designed together with shared open space. Uses not listed "are prohibited unless" the Community and Economic Development Director decides a use is similar to a listed one.

Source: Riverside Municipal Code Tables 19.150.020 A and B; Section 19.443.020.

Three footnotes in the use table matter for small projects. Footnote 2 says "Legal, existing duplexes built prior to the adoption of this Zoning Code are permitted in the R-1-7000 Zone." Footnote 4 lets an owner build "One single-family detached dwelling" in R-3 or R-4 on "one legal lot 0.25 acres in size or less in existence prior to January 1, 2018," under R-1-7000 standards. Footnote 1 of the incidental use table says ADUs are permitted where a primary home exists or is proposed.

Two of those footnotes point to the wrong section. Footnote 2 sends readers to "19.100.060 D," which covers setbacks on small RR lots, and the ADU footnote refers to "Chapter 19.422," while the ADU rules are in Chapter 19.442. Ask the Planning Division if a footnote seems to conflict with the table row it belongs to.

Section 19.100.060 B gives house-lot owners in RE, RA-5, RR and R-1 another option. One "entirely new single-family dwelling" may be built where one house already stands, if the old house is altered into a lawful accessory building or moved off the lot. The owner signs an agreement backed by a bond "in the amount of 100 percent of the amount of the cost of such alterations or removal."

Overlays That Change the Base Zone

An overlay is a second zone laid over the base zone. It adds rules without changing the base zone name. Four overlays in Article VI affect homes most:

• Residential Protection (RP), Chapter 19.219. Its purpose is to stop "the physical conversion of single-family dwellings to higher occupancy rental housing units." Bedrooms may total no more than 50 percent of the home's dwelling area, and common living area must be at least equal to the bedroom area. A home with five or more bedrooms needs one more open parking space. Work that results in "1,000 square feet or less of total dwelling area on a lot" is exempt, and on a lot with ADUs or SB 9 homes the rules "apply individually to each dwelling unit on the lot."
• Building Stories (S), Chapter 19.200. The number after the S on the zoning map sets the story limit, and it "shall take precedence over the height requirement permitted by the underlying zone." Height is capped at 20 feet for the first story plus ten feet for each added story. The S overlay cannot be used in RA-5 or RC.
• Cultural Resources (CR), Chapter 19.195. It marks historic properties and "does not change the use and development standards of the underlying base zone." It tells owners that Title 20 historic review applies.
• Water Course (WC), Chapter 19.230. It marks floodways and stream channels, and "No grading is permitted except as may be authorized for a permitted or conditionally permitted use."

Airports add a further layer. Chapter 19.149 sends some projects near Riverside Municipal Airport, Flabob Airport and March Air Reserve Base/Inland Port Airport to airport land use review, and Table 19.100.040 A tells owners to check it for density and height.

Mixed-Use and Specific Plan Zones

Homes may also go in the three mixed-use zones of Chapter 19.120, which mix shops or offices with housing. MU-N allows 10 homes per acre, MU-V 30 and MU-U 40. Note 4 of the mixed-use table allows up to 40 homes per acre in MU-V and 60 in MU-U within half a mile of a transit stop on Magnolia or University Avenue or of any transit station, and says the extra density is "permissible, not mandatory, and subject to discretion as part of the Site Plan Review process."

Parts of the city sit in specific plan zones instead of the zones above: the Northside Specific Plan Zone (NSP), the Downtown Specific Plan Zone (DSP) and the Orangecrest Specific Plan Zone (OSP). A specific plan is a detailed plan for one area that carries its own zoning rules. Chapter 19.443 names two specific plan districts, DSP-RES and NSP-MDR, as single-family zones where SB 9 applies.

How State Law Fits In

Riverside is a charter city, a city that runs under its own local charter. Charter Section 200 gives it "the power to make and enforce all laws and regulations in respect to municipal affairs, subject only to such restrictions and limitations as may be provided in this Charter and in the Constitution of the State of California." The state housing laws on this guide still apply: the City wrote Chapter 19.443 "to ensure compliance with California Government Code Sections 65852.21 and 66411.7, otherwise known as Senate Bill 9."

So on an R-1 lot, the zone allows one main home, and state law adds ADUs and SB 9 homes. See the ADUs and SB 9 page for the City's rules, and the state pages on SB 9 and ADU law for the statutes.

Where to Go Next

Related on VanPlex: the Riverside overview, is your lot eligible and duplex to fourplex.

Frequently Asked Questions

Official sources (checked October 2026)