Thinking about turning your garage into a guest suite or long-term rental? In unincorporated East County, many homeowners can convert existing garages into accessory dwelling units with fewer hurdles than you might expect. You want clear rules, realistic costs, and a simple path to permits. This guide gives you the essentials so you can plan with confidence and avoid costly delays. Let’s dive in.
Why garage conversions work in East County
Converting a permitted garage into an ADU is allowed under California law and recognized by San Diego County. Because you are reusing an existing structure, you often benefit from more flexible siting and setback rules compared with new construction. State guidance also says you generally do not have to replace off-street parking that is lost when you convert a garage. See the state’s overview in the HCD ADU Handbook and the County’s ADU program page for local implementation.
What current law allows
Recent state updates favor homeowners:
- No owner-occupancy requirement for ADUs. AB 976 prohibits local agencies from requiring the property owner to live on-site for new ADUs. See the statute details on AB 976.
- Faster review with preapproved plans. AB 1332 requires local preapproved-plan programs and sets a 30-day ministerial review for ADUs that use an eligible preapproved plan. Learn how that works from CALBO’s preapproved ADU overview.
- County fee pilot ended. San Diego County’s ADU permit and impact fee waiver pilot ended on January 9, 2024. Budget for normal plan check, permit, impact, and utility fees unless a new program is announced. The County notes this on its ADU page.
Key rules for your lot
Every property is different, but these points matter most for East County garage conversions:
Size and quantity
- Attached ADUs are often limited to 50% of the main home, capped at 1,200 sq ft. Detached ADUs are typically capped at 1,200 sq ft. Existing permitted accessory structures converted to ADUs may be treated differently. Check the County’s permit-ready plans page and confirm your zoning with County PDS.
Setbacks and parking
- When you convert a garage, you are generally not required to add replacement off-street parking, and setback rules are often more flexible for conversions. See the state’s guidance in the HCD ADU Handbook.
Fire safety and WUI areas
- In wildfire-prone zones, you may need ignition-resistant materials, defensible space, and sometimes sprinklers depending on the site and local fire authority. Coordinate early with the County and your fire protection district via the County’s ADU program page.
Septic, sewer, and water
- Many East County parcels are on septic. You must confirm that the existing system can handle added flow. Septic upgrades can be a deciding factor. See a practical overview of septic considerations in this ADU FAQ and contact County Environmental Health early. If you are on public sewer, your district may require capacity checks and connection fees.
HOA and rentals
- HOAs and CC&Rs are limited in how they restrict ADUs, but many require submittals or board review. The state’s ADU resources explain where state law preempts local rules. If you plan to rent, confirm any short-term rental limits with County PDS during permitting.
Step-by-step permitting in unincorporated East County
- Pre-check your status. Verify your property is in unincorporated San Diego County, confirm your APN and zoning, and note whether you are on septic or sewer. Start with the County’s ADU page.
- Choose your path. Decide on a full ADU or a JADU. Conversions are often fastest because they reuse the existing envelope. Review preapproved plans that may fit your footprint on the County’s permit-ready plans page.
- Prepare plans. You will need architectural, structural, energy, and site plans that show utilities, access, and any door or window changes. Using a preapproved plan can shorten review under AB 1332.
- Submit your building permit. Expect ministerial review within 60 days for standard ADU applications or 30 days if you use an eligible preapproved plan. You will respond to plan check comments until your plans meet objective standards.
- Coordinate utilities. Apply with SDG&E for service changes or a new meter using the Apply for Service portal. Contact your water and sewer district and, if on septic, County Environmental Health for required sign-offs.
- Inspections and final sign-off. The County will schedule inspections and issue your final approval when complete. See the County’s broader building permit process on the PDS Building page.
Costs and timelines to expect
Timelines vary with scope and site conditions, but a realistic range helps you plan.
Timeframe
- Plan prep and review often take 2 to 4 months. Conversions can be faster if you use a preapproved plan and respond quickly to comments. Construction and inspections commonly add 3 to 9 months. Utility scheduling or septic upgrades can extend timelines.
Construction cost ranges
- Interior garage conversions often run about $100,000 to $250,000 depending on structural and utility work and finishes. Detached ADUs are usually higher. See ballpark examples from a local ADU cost guide’s construction overview. Always get site-specific bids.
Permit, impact, and utility fees
- The County’s fee waiver pilot ended in early 2024, so plan for normal plan check, permit, and potential impact fees. ADUs under 750 sq ft are often exempt from impact fees under state law. Water, sewer, and power connection or upgrade costs vary by provider.
Common budget surprises
- Electrical service upgrades. Main panel upgrades, trenching, and new meters can add a few thousand to $20,000 or more. See an overview of ADU electrical panel needs and cost factors in this electrical requirements explainer.
- Septic upgrades. Enhanced treatment or expanded leach fields can add several thousand to $20,000-plus depending on soils and design. See septic considerations in this ADU septic FAQ.
- Property taxes. Your ADU is assessed as new construction, which increases your assessed value while your base assessment remains under Prop 13. Review examples in this San Diego ADU property tax guide.
East County pitfalls to avoid
- Waiting on utilities. Apply early with SDG&E and your water or sewer district to avoid schedule drift.
- Skipping septic due diligence. If you are on septic, consult County Environmental Health before you design interior layouts. Bedroom counts affect septic design flow.
- Underestimating fire-zone requirements. If you are in the WUI, budget for ignition-resistant materials, defensible space, and any access improvements required by your fire authority.
Plan your next move
A garage conversion can add flexible living space and long-term rental potential while boosting your home’s appeal. If you are weighing costs, timelines, and the impact on resale, get local, data-informed guidance. For a personalized value check, neighborhood insights, and a clear plan to buy or sell with an ADU in mind, reach out to Tanya Williams.
FAQs
What counts as “unincorporated East County” for a garage conversion?
- Unincorporated areas are outside city limits and are regulated by the County of San Diego. Verify your parcel’s status with County Planning & Development Services using the County’s ADU page as a starting point.
Do I have to replace parking if I convert my garage?
- Generally no. State guidance says jurisdictions cannot require replacement off-street parking solely because you converted a garage to an ADU. See the HCD ADU Handbook.
Can I rent my new ADU without living on the property?
- Yes for ADUs. AB 976 prohibits local owner-occupancy requirements for ADUs. JADUs remain subject to owner-occupancy rules. See the statute text for AB 976.
How fast can I get a permit if I use a preapproved plan?
- If you use an eligible preapproved plan, state law sets a 30-day ministerial review window. Learn more about the program intent at CALBO’s preapproved ADU overview.
What if my property is on septic in East County?
- You must verify your system’s capacity with County Environmental Health. Septic upgrades are common drivers of cost and schedule. See general septic considerations in this ADU septic FAQ.
Will my property taxes go up after the conversion?
- Yes, the ADU is typically assessed as new construction and added to your assessed value. Review examples in this San Diego ADU property tax guide.
