Special zoning regulations apply to ADU construction in Sylmar. ADUs are allowed in residential areas. Checking of zoning regulations is necessary before construction. Our team helps you understand these rules.
The size of the ADU depends on the size and plot size of the main house. The table below gives the maximum allowed area. We help you choose the right size.
| Plot Size | Single-family (maximum floor area) | Duplex and Multi-Family (Maximum Floor Area) |
| 5,000 | 1,400 sq ft | 1,100 sq ft |
| 7,500 | 1,700 sq ft | 1,200 sq ft |
| 10,000 | 2,000 sq ft | 1,400 sq ft |
| 15,000 | 2,500 sq ft | 1,800 sq ft |
| 20,000 | 3,200 sq ft | 2,200 sq ft |
The maximum height of the ADU in Sylmar must be less than the main building. The height of a one-story ADU can be up to fifteen feet. The maximum height of the two-storey ADU is allowed up to twenty-five feet.
Only a maximum of fifty percent of the total area of the plot can be used for building construction. It includes both the main building and the ADU. Our team will help you follow this rule.
The location of the ADU is decided according to the characteristics of your plot. Building an ADU in the back yard is considered the best option. ADUs can also be constructed in the side yard.
Single-Family:
Duplexes and Multi-Family:
The exterior design of the ADU should match the main building. Choose color, material and architectural style carefully. Placement of windows and doors should be done keeping sunlight in mind.
ADU requires an additional parking space. This site can be in a garage or open space. The entrance to the parking lot should be connected to the public road.
It is mandatory to follow setback rules. Place a setback of twenty feet at the front, fifteen feet at the back, and five feet at the sides. These rules protect the privacy of your neighbors.
The table below gives the minimum plot area for different zones.
| zone | Minimum Plot Area |
| R-20 | 6,000 sq. ft. |
| R-10 | 8,500 sq. ft. |
| R-7 | 11,000 sq. ft. |
| R-5 | 16,000 sq. ft. |
| R-2.5 | 21,000 sq. ft. |
ADUs are required to arrange independent utility connections. Separate meters and connections for electricity, water and sewer are installed. Our team helps you get all the necessary permits. Approval from local departments must be taken for utility connections.
Future needs are considered when planning a utility connection. The diameter of the water pipeline, the power capacity and the size of the sewer line should be correct. We offer you the best technical solutions. The appropriate material for connection is selected.
Smoke detectors and fire extinguishers are mandatory for fire safety. There should be an emergency exit. The size of the windows should be suitable for emergency evacuation. Safety rules are strictly followed.
Special permits are required to deliver short-term rentals. It is important to follow the rules for business activities. Home office is allowed at ADU. The rental period cannot be less than thirty days.
It is mandatory to follow the Building Construction Code. Special attention is paid to safety standards. Adherence to electrical and plumbing codes is required. The inspection process is carried out regularly.
Follow the permit application process carefully. Submit all the required documents on time. Be prepared in time for inspections. The table below shows the cost of different permits.
| Permit Type | cost |
| Building Permits | $2,500 – $5,500 |
| Electrical Permit | $300 – $600 |
| Plumbing Permit | $300 – $900 |
| Mechanical Permit | $200 – $600 |
| Demolition Permit | $150 – $300 |
| Landscaping Permit | $100 – $200 |
The area of the property must meet the minimum requirements. The slope of the land should be less than fifteen percent. Soil test report is required. There should be proper drainage system.
A car parking lot is mandatory for ADU. The size of the parking lot should be nine feet by eighteen feet. Build a paved surface in the parking lot. Leave enough space for vehicular movement.
A setback of twenty feet on the road side is mandatory. Make provision for landscaping at the front. Leave proper space for the entrance. Take care of the visual aesthetic.
It is necessary to keep the side setback five feet and the rear setback fifteen feet. Take care of the neighbor’s privacy. Leave space for emergency exits. Trees can be planted in the setback.
Provision of open space is necessary. Leave space for children to play. Maintain greenery in the back courtyard. Ensure natural light and air flow.
We provide the services of ADU construction at all eligible properties in Sylmar. All properties located in a residential area are eligible for ADU. The size and condition of the land are important factors. Our team verifies the eligibility by evaluating your property.
Our experts recommend the best ADU options by inspecting your property. Plot size, slope and existing structures are considered. Environmental factors are also evaluated. We ensure adherence to local rules and regulations.
The junior ADU is built inside the main building. Its size should be less than five hundred square feet. The kitchen can be shared. Separate entrance is required.
We have pre-approved ADU designs available. These designs meet all regulations and standards. They can be constructed faster. The cost is also low.
These designs are available for different sizes and budgets. Each design includes modern features. The quality of construction is supreme. You can choose according to your requirement.
Start your ADU project with ADU Builders CA today. Our expert team will guide you. Contact us for a free consultation. We will help you create the ADU of dreams.
Fire sprinklers are only required if the primary dwelling also has them.
ADUs typically require a minimum setback of 4 feet from property lines.
Separate utility connections are optional but not mandatory for most ADUs.
The checklist includes design review, site plans, structural plans, permits, and financing.
You need site plans, floor plans, construction details, and a permit application.
Inspections typically include foundation, framing, plumbing, electrical, and final review.
Work with licensed professionals to design and construct your ADU to code.
You may need to revise and resubmit plans to the Sylmar planning office.
Submit complete and accurate documents and work with professionals to avoid delays.
ADUs under 750 sq. ft. are exempt from impact fees.
Yes, it includes checking structure, utilities, and obtaining conversion permits.
Yes, ADUs must meet height, size, and setback requirements, and their design should complement the primary dwelling.
Yes, but you need to ensure the ADU fits within allowable lot coverage and setback rules.
ADUs must comply with California Building Codes, including foundation, framing, insulation, plumbing, and electrical requirements.
Yes, ADUs must comply with California Energy Code (Title 24) and include energy-efficient windows, insulation, and appliances.
You must submit a revised plan to the Sylmar Building Department and may incur additional fees or inspections.
Yes, ADUs near high-noise areas (e.g., busy roads) must include soundproofing measures such as double-glazed windows.
Yes, you can appeal to the city’s Planning Commission or seek adjustments to meet requirements.
Lot coverage varies by zoning but generally allows for up to 50% of the lot to be developed, including the primary dwelling and ADU.
