Community Development

All individuals and businesses doing work within city limits, whether or not they have a physical structure in the city, are required to have a business license. This includes contractors, internet and home-based businesses. Applications and renewals are processed online at City Hall. Fees are determined at the time of application submission. Contact the Planning Division at 909-839-7030.

Learn about the rules on the Garage and Yard Sales page. 

If you are planning renovations or new construction in or around your property, chances are you will need to obtain a building permit. Taking out a permit before commencing your construction project not only keeps you in compliance with City law, but also protects you and your investment - be it a home or a business. For more information, contact the Building and Safety Division.

The Neighborhood Improvement Officers enforce all City Municipal Codes applicable in the community, including the provision against the open storage of junk. This code states that front and side yards shall be kept and maintained free and clear of:

• Appliances
• Camper Shells
• Construction and automotive materials or parts
• Discarded or Broken Materials
• Equipment
• Furniture
• Inoperative Motor Vehicles
• Junk
• Trash, Refuse, and Debris

If a property is found not in compliance with the code, a notice of violation is sent to the owner allowing a certain number of days to correct the violation. If a violation is not corrected within the time allowed, the owner may be fined. Any debris that is found, which is associated with the code violation, may be removed by a contractor at the property owner's expense. Failure to pay the fine will result in a lien being placed against the property. For more information, call 909-839-7030 or submit a request. 

The City's Municipal Code states that exterior holiday lights and decorations must be removed within 30 days of installation, and no later than mid January. Besides contributing to blight, keeping holiday lights installed for an extended period of time creates the potential for a fire hazard because of their temporary-use nature. Homeowners found not to be in compliance will be issued a courtesy notice to correct violation within 10 days. Failing to remove the lights within the allotted time frame can result in a $100 fine.

Yes. All vehicles that are being repaired, dismantled, or incapable of operating are considered "inoperable" and must be stored out of public view, such as in the garage, when possible. It is considered a violation of the City Code if the vehicle or its parts become a hazard to the public health and safety. To report, contact the Neighborhood Improvement Division at 909-839-7030.

All residentially-zoned properties are eligible to construct one ADU and one Junior ADU (JADU), regardless of lot size. For studios and one-bedroom ADUs, 850 square feet is allowed and up to 1,000 square feet for 2 or more bedrooms. A JADU is created within the walls of a single-family residence and may share central systems and restrooms with the primary residence, and must contain a basic kitchen. JADUs are allowed up to 500 square feet. Refer to the Development Code Section 22.42.120 for additional ADU requirements - https://library.municode.com/ca/diamond_bar/codes/code_of_ordinances?nodeId=CICO_TIT22DECO_ARTIIISIPLGEDEST_CH22.42STSPLAUS_S22.42.110REACUSST.

 Once you have plans ready, you may submit through the Planning inquiry form. No additional forms are required at this stage. Please allow a few days for the Planning and Building and Safety Divisions to review for completeness. Once authorization is received, a planner will instruct you on the next steps for formal building plan check submittal to the Building and Safety Division. There is a 15-working day turnaround once accepted by the Building and Safety Division. Every subsequent submittal is 10 working days. When all comments/corrections have been addressed, your permit will be issued for the ADU.

Short-term rentals, such as those listed on Airbnb and similar sites, are prohibited in all residential zones within Diamond Bar.  The Diamond Bar Municipal Code defines a hotel or motel as “facilities with guest rooms or suites, provided with or without kitchen facilities, rented to the general public for transient lodging (less than 30 days).” By definition, a residence being rented to a tenant for fewer than 30 days is, therefore, classified as a hotel/motel, and is not a permissible use in residential zones pursuant to the City’s land use table. For more information, refer to Sec. 22.08.030. and Sec. 22.80.020. of the Diamond Bar Municipal Code.

The Diamond Bar Zoning Map designates existing land use classifications for each parcel located within the city. In addition to land use types (residential, commercial, and open space/conservation), the map also indicates the density of housing development allowed such as Low Medium Density Residential (RLM), Medium High Density Residential (RMH), and High Density Residential (RH). The Zoning Map is available online as part of the City’s GIS mapping database. To view the Zoning Map, click the Layers List icon on the top right corner and select “Zoning.” For more information, contact the Planning Division at (909) 839-7030 or planning@diamondbarca.gov. 

The Los Angeles County Development Authority (LACDA) offers two programs to assist first-time homebuyers: the Home Ownership Program (HOP) and the Mortgage Credit Certificate (MCC) Program.

HOP provides a second mortgage loan with an assistance amount of up to $85,000, or 20%, of the purchase price as well as assistance with the down payment and/or closing costs, whereas the MCC program offers a federal income tax credit of up to 20% of the annual interest paid on the mortgage loan.