Special zoning rules apply to ADUs in Westlake Village. Forming ADUs is allowed in residential areas, but there may be restrictions in some areas. According to city regulations, ADUs can be constructed alongside the main building or separately. There are also rules for minimum size of land and building coverage for ADUs.
The size of the ADU depends on the size of the plot and the following rules must be followed:
| Lot Size | Single-Family (Maximum Floor Area Allowed) | Duplex and Multi-Family (Maximum Floor Area Allowed) |
| 4,500 | 1,100 sq ft | 700 sq ft |
| 6,500 | 1,400 sq ft | 900 sq ft |
| 9,000 | 1,700 sq ft | 1,100 sq ft |
| 14,000 | 2,200 sq ft | 1,400 sq ft |
| 19,000 | 2,800 sq ft | 1,800 sq ft |
It is very important to follow the height limit of ADU in Westlake Village. The maximum height of a one-story ADU can be up to fifteen feet from the street. For two-storey ADUs, this limit has been set at twenty-five feet. The height in mountainous areas is calculated according to the slope.
The total building coverage limit is set with ADU on the plot. The main house and the ADU together can cover a maximum of fifty percent of the land. It is necessary to leave open space so that proper arrangement of air and light is maintained.
Single-Family Homes:
Duplexes and Multi-family:
The exterior design of the ADU should match the main house. Choose the color, material and architectural style carefully. The size and location of windows and doors should be as per the prescribed standards. The slope of the roof and the texture of the exterior walls should be adapted to the local weather.
An additional parking space will have to be arranged for the ADU. This venue can be in the garage or in the open. Access to the parking area should be easy. Parking rules may be relaxed for ADUs located close to public transport.
It is necessary to keep a minimum distance between the ADU and the boundary of the plot. Twenty feet in front, fifteen feet in the back, and ten feet in the side are mandatory. Create buffer zones keeping in mind the privacy of the neighbor.
| Zone | Minimum Lot Area |
| R-18 | 4,800 sq. ft. |
| R-9 | 7,200 sq. ft. |
| R-6 | 9,500 sq. ft. |
| R-4 | 14,500 sq. ft. |
| R-2 | 19,500 sq. ft. |
Independent electricity connection will have to be arranged for ADU. Place the meter box and wiring system in a safe place. Water connection can be taken from the main line. Special permits will be required for new sewer connections.
Plan separately for gas and internet connections. Contact utility companies in advance. Ensure easy access to meters and connection points. All connections must conform to local building codes.
There should be complete fire safety arrangements in ADU. Smoke detectors and fire extinguisher are mandatory. Clearly mark the way to the emergency exit. Doors and windows should be made of fire-resistant material.
Special permits are required to rent short-term to ADUs in Westlake Village. Different rules apply to business activities at ADU. The tenant cannot be retained for less than thirty days. Home offices are allowed, but the movement of customers is restricted.
ADUs must be constructed in accordance with California building codes. Select building materials and techniques in conformity with recognized standards. Electrical and plumbing systems to be installed in accordance with safety standards. Make provision for regular inspection.
Submit all the necessary documents to obtain the permit. Construction plans and building maps should be clear. Submit the permit fee on time. Follow the timetable for inspection.
| Permit Type | Cost |
| Building Permit | $2,500 – $5,500 |
| Electrical Permit | $300 – $600 |
| Plumbing Permit | $250 – $450 |
| Mechanical Permit | $200 – $400 |
| Demolition Permit | $150 – $300 |
| Landscaping Permit | $100 – $200 |
The size of the property should be suitable for ADU construction. The ground should be flat or sloping. Conduct soil testing and geological surveys. Assess the risk of natural disasters such as floods or earthquakes.
A car parking lot is mandatory for ADUs. The parking area should be paved and level. Leave enough space for vehicular movement. Build the garage or carport according to the rules.
It is necessary to leave a setback of twenty feet on the road side. Plan landscaping in the front yard. The path to the main entrance should be clear. Take care of beauty and safety.
A setback of five feet on the side and ten feet at the rear is required. Take care of the neighbor’s privacy. You can plant trees in the setback area. Leave space for drain and utility lines.
It is necessary to maintain a minimum of twenty percent of the open space. Decide for children’s play and seating areas. Leave proper space for the garden and lawn. Arrange drainage of rain water.
Both single-family and multi-family properties in Westlake Village are eligible for ADUs. The minimum size of the land should be four thousand square feet. There should not be any existing debt or dispute over the property.
Special permission will be required for ADUs in buildings of historical importance. Additional safety measures will be required in areas prone to natural disasters. There should be no legal impediments in the use of the land.
Multifamily properties
The junior ADU is built inside the main house. Its size cannot exceed five hundred square feet. Arrange a compact cooking unit for the kitchen. The bathroom can be shared with the main house.
Some standard ADU designs are already approved in Westlake Village. Selecting these designs speeds up the permit process. Permission for changes to the pre-approved design is limited. Construction costs can be estimated in advance.
These designs offer options ranging from one bedroom to two bedrooms. All necessary features and safety standards are included. Designed to suit the local climate and architecture. Durable materials have been used for ease of maintenance.
We are ready to assist you every step of the way in your ADU project. Our expert team will guide you through the entire process from design to construction. Get in touch today and take the first step towards realizing the ADU of your dreams.
Yes, either the ADU or the primary residence can be owner-occupied or rented.
Yes, properties with HOAs must adhere to both HOA rules and city regulations.
Yes, having both is allowed under California state law.
Inspections for foundation, framing, plumbing, electrical, and final completion are common.
Yes, using pre-approved plans can streamline the permitting process.
Yes, but additional restrictions may apply to preserve the historic character.
Yes, ADUs should match the architectural style of the main residence.
