Riverside Zoning and ADU Guide for Homeowners and Sellers

Last updated November 13, 2026. Reviewed by the Cash Home Buyers CA team. Information comes from the City of Riverside; sources are listed at the end.

Riverside allows three kinds of accessory units, ADUs, junior ADUs and moveable ADUs, and its FAQ says the owner does not have to live on site for an ADU or MADU, but a JADU carries a recorded owner-occupancy deed restriction. A building permit is required for any of them.

Riverside ADU rules at a glance

Who administers it	City of Riverside CEDD: Planning and Building and Safety; One Stop Shop (951) 826-5800
Permit	A building permit is required; plans must be prepared by a licensed design professional; Building and Safety at (951) 826-5697
Detached ADU size	Up to 1,200 sq ft of livable space
Attached ADU size	Up to 1,200 sq ft or 50% of the primary dwelling, whichever is less, with at least 850 sq ft guaranteed for one bedroom and 1,000 sq ft for two or more
JADU	Up to 500 sq ft, within the walls of the primary dwelling; owner occupancy required on one of the units by recorded deed restriction
MADU	Premanufactured unit on a chassis, 150 to 430 sq ft
Setbacks	New one-story ADUs and MADUs under 16 ft: at least 4 ft from side and rear lines; taller ADUs follow the primary dwelling’s side and rear setbacks
Parking	No additional parking required for an ADU; no replacement parking if a garage or carport is converted
Rentals	ADUs and MADUs may be rented separately for longer than 30 days

What do the owner-occupancy rules mean for a seller?

If your Riverside house has a permitted ADU, the city says the owner need not live on the property to rent to other occupants, which keeps investor buyers in play.

A junior ADU is different: the recorded deed restriction binds current and future residents to owner occupancy on at least one unit. Confirm in the city’s permit records that the unit was permitted and finaled before you market it as a legal second unit. These FAQs are dated, so check with the city for current standards.

How ADUs and zoning affect selling a house in Riverside

A permitted ADU can be a selling point, but a converted garage or backyard unit with no permit is something buyers’ inspectors and lenders flag. In California, sellers generally have to disclose known unpermitted work. Your choices are to permit the unit, remove it, discount the price, or sell as-is to a cash buyer who accounts for the risk. See our Riverside building permits guide for the lookup tools.

How to sell a house in Riverside with an unpermitted ADU

1. Check the permit record. Search the address in Permits Online to see whether the unit was ever permitted.
2. Check for complaints. Ask Code Enforcement at (951) 826-5633 whether any case is open.
3. Weigh the options. Permit it, convert it back, sell with a credit, or sell as-is.
4. Disclose honestly. A cash offer does not change what you must disclose, but it removes repairs and inspections from the timeline.

We buy Riverside houses as they are, including houses with converted garages and backyard units. Read how selling a house as-is in Riverside works, or see cash home buyers in Riverside. If the house has been cited, read our Riverside code enforcement guide.

Not sure whether your unit is legal? Call (424) 435-2326 or request a cash offer. There is no cost and no obligation.

Reading the three unit types when you list

Riverside treats an ADU, a junior ADU and a moveable ADU as different things, and the difference matters at sale time. A full ADU is a separate living space on the lot, attached or detached. A JADU is carved out of the existing house and tops out at 500 square feet.

A MADU is a factory-built unit on a chassis, from 150 to 430 square feet. If your listing or disclosure calls a space an ADU, a buyer’s agent will ask which of the three it is and whether the city permitted it as that type. Having the answer ready, from a final permit record, makes the sale easier.

The state law behind Riverside’s rules

Most of Riverside’s ADU standards follow California Government Code section 66314 and the sections around it.

Under the state framework, a city must act on a complete ADU application within 60 days, may not require replacement parking when a garage is converted, and cannot impose impact fees on units under 750 square feet.

State law also guarantees an ADU of up to 800 square feet with four-foot side and rear setbacks. Riverside’s own numbers, such as the 1,200 square foot detached limit, sit on top of that floor, so a unit that fits the state minimum is generally safe from a size challenge. Confirm current details with the city, since the rules are amended often.

Is the unit legal? A four-point check

1. Permit. Is there a building permit for the unit, and was it finaled?
2. Size and type. Does the built size match the approved plans and fit the limits for its type?
3. Setbacks. Was it built at least four feet from the side and rear lines, or at the primary home’s setback if taller than 16 feet?
4. Systems. Do the kitchen, bath, electrical and heating match what was inspected?

A no on any point does not stop a sale. It tells you what to disclose and what a cash buyer will price in.

Older unpermitted units and enforcement

California Health and Safety Code section 17980.12 lets an owner of certain pre-2020 unpermitted ADUs ask the enforcement agency to delay enforcement for up to five years when the unit does not present a health and safety problem.

Whether it applies depends on the unit’s age and condition, so ask the city rather than assume. Separately, a seller should know that a unit rented without a permit can draw a complaint, which is why the Riverside code enforcement guide linked above is worth reading alongside this one.

Selling the house with a unit or planning to

Riverside says a legal ADU or MADU can be rented separately for more than 30 days and the owner need not live on site, which can widen your buyer pool to investors. If you instead plan to remove the unit before selling, check whether a demolition permit is needed. If the cost, time or risk of a permit is not worth it, a cash sale as-is avoids both.

More Riverside ADU questions

Does Riverside require extra parking for an ADU?

The city says no additional parking is required for an ADU, and replacement parking is not required when a garage or carport is converted.

How long can an ADU be rented in Riverside?

The city’s FAQ says ADUs and MADUs may be rented separately for longer than 30 days.

What is a moveable ADU?

The city describes a MADU as a premanufactured unit on a chassis, between 150 and 430 square feet.

Riverside zoning and ADU FAQ

Do I have to live on my Riverside property if it has an ADU?

The city’s FAQ says the owner does not have to occupy a unit to rent an ADU or MADU, but a JADU requires owner occupancy on at least one unit through a recorded deed restriction.

How big can an ADU be in Riverside?

Per the city’s FAQ, detached ADUs may be up to 1,200 square feet, attached ADUs up to 1,200 square feet or half the primary dwelling, and JADUs up to 500 square feet.

Can I sell a Riverside house with an unpermitted ADU?

Yes. The sale is not legally blocked, but you should disclose the unit. A cash buyer can purchase the house as-is with the unit unpermitted.

Is a permit required to build an ADU in Riverside?

Yes. The city says a building permit is required, with plans prepared by a licensed design professional and plan check and permit fees applying.

Sources

• City of Riverside: ADU, JADU and MADU FAQs
• City of Riverside CEDD: Dwell Riverside
• California Government Code section 66314 (ADU standards)
• California Health and Safety Code section 17980.12 (enforcement delay)

This guide is general information, not legal advice. ADU rules change often; confirm requirements with the City of Riverside.