Glendora Zoning and ADU Guide for Homeowners

Last updated November 13, 2026. Reviewed by the Cash Home Buyers CA team.

If you own a house in Glendora with a converted garage, a backyard cottage, or an extra unit you are not sure is legal, the city’s zoning rules decide what a buyer can use and what a lender will count.

This guide summarizes what the City of Glendora publishes about accessory dwelling units (ADUs), junior ADUs (JADUs), SB 9 and accessory buildings, based on the city’s planning pages and Chapter 21.04 of the Glendora Municipal Code.

Glendora ADU rules at a glance

Topic	What the city says
Governing code	Glendora Municipal Code Section 21.04.040 (ADU and JADU standards)
Where ADUs are allowed	Any lot where single-family or multifamily dwellings are permitted, with a proposed or existing home on the same lot
Number in a single-family zone	One ADU on the lot, with a JADU handled separately
Unit that cannot be blocked	An ADU up to 1,200 square feet with four-foot side and rear setbacks that otherwise meets local design standards
JADU size	No more than 500 square feet, within the walls of an existing or proposed single-family home, plus up to 150 additional square feet for an entry
JADU owner occupancy	Owner must live in the main house or the JADU
Detached accessory buildings	Set back at least four feet from side and rear lines and no closer to the street than the front and street-side setbacks
Rental term	The city’s ADU handout lists a rental term of no less than 30 days
High fire hazard areas	No ADU in a very high fire hazard severity zone if the lot is not served by a street that meets city standards

What counts as an ADU in Glendora

The city defines an ADU as a separate living space on the same lot as a primary home, attached or detached, with full living, sleeping, eating, cooking and sanitation facilities. A junior ADU is a smaller unit created inside an existing or proposed single-family house.

The city’s planning page groups ADUs together with SB 9, the state law that lets some owners of single-family lots build up to two units or split a lot, and it publishes a handout, an SB 9 handout, SB 9 lot split requirements, an ownership affidavit and a sample JADU covenant agreement.

Design and site standards

Beyond size, Glendora’s code ties ADUs to its site layout and building orientation rules in Chapter 21.15.040 and its architectural style requirements, and it requires the unit’s address to be clearly labeled on the main entrance, with a second address marking visible from the street when the entrance cannot be seen from the street the main house faces.

The code also says an ADU must comply with lot coverage, floor area ratio, open space and limits on the number and size of accessory structures, which is where many garage and cottage plans run into trouble.

JADU rules that affect a sale

A JADU needs the property owner to occupy either the main home or the JADU, and the city’s page notes a deed restriction when the JADU shares a bathroom. A deed restriction recorded against the property travels with it, so a buyer takes the house subject to those conditions. If you are selling a house with a JADU, locate the recorded covenant and the permit paperwork before you list.

Updates to the ordinance

The city’s ADU handout carries a July 2025 date, and a state environmental filing lists a proposed ordinance to amend Title 21 of the Glendora Municipal Code to update ADU and SB 9 regulations. Rules like these change as California law changes, so confirm the current standards with the Planning Division before you design or buy based on a specific number.

Unpermitted units and garage conversions

A garage converted without a permit, a room added without plans, or a rental unit with no permit history is a common problem in older Glendora neighborhoods. It can raise insurance questions, complicate an appraisal, and lead to citations. Our building permits guide explains how to look up permit history, and our code enforcement guide explains citations and fines.

How to sell a house in Glendora with an ADU or unpermitted unit

• Pull the permit record and any recorded JADU covenant for your address.
• Confirm with Planning whether the unit meets current standards or can be legalized.
• Get a contractor estimate for legalizing the unit versus removing it.
• Decide whether to legalize and list, disclose and discount, or sell as-is.
• Tell buyers plainly what is permitted and what is not; undisclosed units are a frequent source of disputes after closing.

Cash Home Buyers CA purchases Glendora houses with ADUs, converted garages and unpermitted additions as-is, with no repairs, no commissions and a closing date you choose. Visit our Glendora cash home buyer page or use the form at the top of this page.

Frequently asked questions

Where are ADUs allowed in Glendora?

On any lot where single-family or multifamily dwellings are permitted and that has a proposed or existing home. In a single-family zone the code allows one ADU on the lot.

How big can an ADU be in Glendora?

The code says local zoning cannot block an ADU of up to 1,200 square feet that keeps four-foot side and rear setbacks and meets other design standards. Check Section 21.04.040 and the city handout for current limits that apply to your lot.

What is the size limit for a junior ADU?

500 square feet, built within the walls of an existing or proposed single-family home, with up to 150 additional square feet allowed for an entry.

Do I have to live on the property if I have a JADU?

Yes. The city says the owner must live in either the main home or the JADU, and a deed restriction is required if the JADU shares a bathroom.

Can I rent an ADU short term?

The city’s ADU handout lists a rental term of no less than 30 days. Confirm the current wording with the Planning Division.

Can I sell a Glendora house with an unpermitted unit?

Yes. You can legalize it first, disclose it and price accordingly, or sell as-is to a buyer who purchases homes in any condition.

More Glendora guides

• Glendora building permits guide
• Glendora code enforcement guide
• We buy houses in Glendora, CA
• We buy houses in Los Angeles County

Sources

• City of Glendora: Accessory Dwelling Units and SB 9
• City of Glendora: ADU, JADU and guest house standards handout
• Glendora Municipal Code Chapter 21.04, Residential Zones
• City of Glendora: Planning
• CEQAnet: Accessory Dwelling Unit and SB 9 Regulations

This guide is general information from public sources, not legal advice. Confirm current rules with the city.