Introduction
In Redwood City, the rules and regulations governing Accessory Dwelling Units (ADUs) are designed to balance the need for additional housing with the preservation of neighborhood character. Redwood City provides clear guidelines to streamline the ADU development process, ensuring homeowners can enhance their properties without compromising on safety or aesthetic values. ‘ADU Specialist Bay Area’ offers comprehensive assistance, from navigating complex zoning laws to obtaining necessary permits, ensuring a smooth and efficient ADU construction process.
Essential ADU Rules for Redwood City
What you can build
Maximum size
Up to 1,200 square feet.
Side / rear setbacks
Minimum of 4 feet.
Two stories
Permitted with restrictions.
Building separation
Minimum of 6 feet from the main dwelling.
Permitting timeline
Standard
Approximately 60 days.
Coastal
Not applicable in Redwood City.
Zoning Regulations in Redwood City
Redwood City’s zoning regulations for ADUs are straightforward, aiming to maintain neighborhood integrity while allowing for additional housing. Most residential zones permit ADU construction, subject to specific criteria.
ADU Size Limitations
| Lot Size | Single-Family (Maximum Floor Area Allowed) | Duplex and Multi-Family (Maximum Floor Area Allowed) |
| Under 7000 | 800 sq ft | Not permitted |
| 7000 - 9999 | 900 sq ft | 1 ADU + 500 sq ft per existing unit (up to 1100 sq ft max) |
| 10000 - 12999 | 1000 sq ft | 1 ADU + 550 sq ft per existing unit (up to 1150 sq ft max) |
| 13000 - 19999 | 1100 sq ft | 1 ADU + 600 sq ft per existing unit (up to 1200 sq ft max) |
| 20000+ | 1200 sq ft | 1 ADU + 650 sq ft per existing unit (up to 1250 sq ft max) |
ADU Height Limitations
ADUs in Redwood City can be built up to a maximum height of 16 feet, ensuring they blend well with existing neighborhood structures.
Building Coverage
The total building coverage for the property, including the ADU, must not exceed 50% of the lot area.
Location
| Property Type | Location Requirement |
| Single-Family Homes | Attached ADUs: Integrated into the main structure. |
| Detached ADUs: Located in the rear yard. | |
| Junior ADUs (JADUs): Must be within the existing primary dwelling. | |
| Duplex and Multifamily | Attached ADUs: Integrated into the primary structure. |
| Detached ADUs: Positioned in the rear or side yard. |
Exterior details
ADUs must match the architectural style and materials of the primary residence to maintain neighborhood aesthetics.
Parking
One parking space per ADU is required, which can be provided as tandem parking on an existing driveway.
Setbacks and buffer zones
ADUs must maintain a minimum setback of 4 feet from side and rear property lines.
Minimum Lot Area
| Lot Size | Minimum Lot Area for ADU | Description |
| Under 7000 | ADUs not permitted | Smaller lots cannot accommodate ADUs. |
| 7000 - 9999 | 7000 sq ft | Suitable for smaller ADUs. |
| 10000 - 12999 | 10000 sq ft | Allows for larger ADUs. |
| 13000 - 19999 | 13000 sq ft | Adequate for medium-sized ADUs. |
| 20000+ | No minimum lot area requirement | Large lots have flexible options. |
Connection for utilities
ADUs must have separate utility connections for water, sewer, and electricity, ensuring independence from the primary dwelling.
Fire safety
All ADUs must include fire safety features such as smoke detectors, fire extinguishers, and accessible escape routes.
Room specifications
- Sleeping Areas: Minimum of 70 square feet per sleeping area.
- Kitchen: Must include a sink, cooking appliance, and refrigeration facilities.
- Bathroom: Requires a toilet, sink, and bathing facilities.
- Storage: Minimum of 24 square feet of storage space.
Short-term Rentals and Home Occupations Regulations
ADUs can be rented out on a short-term basis and used for home occupations, provided they comply with local business licensing requirements.
Building Codes
ADUs must adhere to all relevant building codes, including electrical, plumbing, and mechanical standards.
Redwood City ADU Permit Guidelines
| Permit Type | Description | Estimated Fee |
| Building Permit | Required for ADU construction. | $2500 - $5000 |
| Electrical Permit | Required for electrical work. | $400 - $700 |
| Plumbing Permit | Required for plumbing work. | $400 - $700 |
| Mechanical Permit | Required for HVAC systems. | $400 - $700 |
| Grading Permit | Needed for site grading. | $300 - $500 |
| Site Development Permit | Required for site improvements. | $300 - $500 |
| Zoning Permit | Required for zoning compliance. | $200 - $400 |
Property requirements
Properties must meet specific requirements, including lot size, setbacks, and zoning regulations, to qualify for ADU construction.
Parking
One additional parking space is required for each ADU, except in cases where the property is within half a mile of public transit.
Front setbacks
A minimum front setback of 20 feet is required for all ADUs to maintain consistent neighborhood aesthetics.
Side and rear setbacks
ADUs must maintain a minimum side and rear setback of 4 feet to ensure privacy and safety.
Open space and rear yards
At least 20% of the lot must be maintained as open space, and rear yards should not be completely covered by ADUs.
Properties That Qualify
To determine your property’s eligibility for ADU development, contact the Redwood City Planning Department.
- Verify that your property is within Redwood City’s jurisdiction.
- Check the specific residential zones that permit ADUs. Common zones in Redwood City include R-1, R-2, and R-M.
- Other General Plan designations that permit ADUs:
- Residential Mixed-Use (RMU): Allows integration of residential and commercial uses.
- Transit-Oriented Development (TOD): Encourages higher density near transit hubs.
- Specific Plan areas: Tailored regulations to support community goals.
Development standards
Single-family
- Attached: Must be integrated into the main structure, sharing at least one wall.
- Detached: Must be located in the rear yard, separate from the main dwelling.
Duplex properties
- Attached: Can be added to either unit in the duplex.
- Detached: Must be placed in the rear or side yard.
Multifamily properties
- Attached: Limited to the conversion of non-livable space.
- Detached: Limited to two detached ADUs per lot.
Junior ADUs (JADUs)
JADUs must be contained within the existing single-family home, utilizing existing square footage.
Property designations
- Flood Zones: ADUs must comply with floodplain management regulations.
- Geohazard Zones: Construction must adhere to additional safety measures in these areas.
- Historic Designation: ADUs must meet specific design and preservation standards.
- Easements: No ADUs can be built on property areas designated as easements.
Summary
Redwood City offers a supportive environment for the development of ADUs, with clear regulations designed to enhance housing options while preserving community character. ADU Specialist Bay Area is here to assist homeowners in navigating the complexities of ADU construction, ensuring compliance with all local regulations and codes.
FAQ
ADUs must maintain a minimum setback of 4 feet from side and rear property lines, ensuring privacy and safety.
Yes, ADUs can be rented out on a short-term basis, provided they comply with local business licensing requirements.
ADUs can be built up to a maximum height of 16 feet, ensuring they blend well with existing neighborhood structures.
Yes, ADUs must have separate utility connections for water, sewer, and electricity, ensuring independence from the primary dwelling.
ADUs can be up to 1,200 square feet in size, depending on the lot size and other zoning requirements.
ADUs must match the architectural style and materials of the primary residence to maintain neighborhood aesthetics.
One additional parking space is required for each ADU, except in cases where the property is within half a mile of public transit.
Yes, but ADUs on historic properties must meet specific design and preservation standards to maintain the historical character.
Properties within Redwood City’s jurisdiction that meet specific zoning and lot size requirements qualify for ADU construction.
Homeowners must submit an application to the Redwood City Planning Department, including plans and necessary documentation, for review and approval.
Yes, ADUs can be either attached to or detached from the main dwelling, depending on the property’s layout and zoning regulations.
Common residential zones that permit ADUs in Redwood City include R-1, R-2, and R-M.
ADUs must adhere to all relevant building codes, including electrical, plumbing, and mechanical standards.
Yes, but ADUs in flood zones must comply with floodplain management regulations to ensure safety.
ADUs are not permitted on lots under 7000 sq ft in Redwood City.
Yes, ADUs in geohazard zones must adhere to additional safety measures to mitigate risks associated with geological hazards.
The minimum lot area required for an ADU in this range is 7000 sq ft.
Yes, ADUs can be used for home occupations, provided they comply with local business licensing requirements.
ADUs must include specific room sizes and features, such as minimum square footage for sleeping areas, kitchen requirements, and bathroom facilities.
No, ADUs cannot be built on property areas designated as easements to avoid interference with utility and access rights.
JADUs must be contained within the existing single-family home, utilizing existing square footage without expanding the building footprint.
Yes, at least 20% of the lot must be maintained as open space, ensuring that the property is not overly built-up.
A minimum front setback of 20 feet is required for all ADUs to maintain consistent neighborhood aesthetics.
The total building coverage for the property, including the ADU, must not exceed 50% of the lot area.
ADUs must match the architectural style and materials of the primary residence to maintain neighborhood aesthetics and coherence.
