San Diego has become one of the most active ADU markets in the country. Many investors now build a main home with several accessory units, or a small multi-unit building, on lots that once held one house.
In short: LendingStreet finances ground-up construction in San Diego for investors building 1 to 8 units, including a home with ADUs, duplexes, townhomes and small 5-8 unit buildings. Loans are sized on loan-to-cost, terms are set per project, and funds are released through inspected draws. Coastal zone review, canyon and hillside lots, and state energy rules are the local issues that move timelines and budgets.
High home prices and steady rental demand from the military, universities, biotech and tourism make new rental units valuable. San Diego's ADU rules, together with state law, have let many investors add multiple units behind or beside a primary home. The city has revised its ADU bonus program over time, so confirm the current rules for your lot.
Neighborhoods like City Heights, North Park, Normal Heights, Encanto, Clairemont and Linda Vista see much of this infill. Coastal neighborhoods face more review and higher land costs.
Many San Diego investors use a two-step plan: build the main home and ADUs, lease them all, then refinance into a DSCR loan using the combined rent. That works best when each unit has its own entrance, meter plan and parking that matches the rules. Some areas also have local incentive programs with affordability requirements for added units. If you use one, include those rent limits in your refinance math.
Typical San Diego 1-8 unit construction projects: Each type has its own exit and its own local issues.
| Project type | Where it is common | Local note |
|---|---|---|
| Main home plus ADUs | City Heights, Encanto, Clairemont | Rental exit; confirm current ADU rules |
| Duplex or townhomes | North Park, Normal Heights | Sale or rental exit |
| Small 5-8 unit building | Transit corridors | Larger review; check incentive programs |
| Spec single-family | Inland and hillside lots | Grading and fire rules affect cost |
Permits run through the city's Development Services Department. Lots in the coastal zone may need a coastal development permit, which adds review time. Lots near canyons can fall under environmentally sensitive lands rules that limit where you can build.
California's Title 24 energy code applies, including solar requirements on most new low-rise residential buildings. Fire hazard severity zones near canyons can require ignition-resistant materials and defensible space.
Many San Diego lots slope toward canyons, which can mean grading permits, retaining walls and drainage work. Fire risk has also tightened the insurance market in California, so get a quote for the finished property before you rely on the rental numbers.
Three things drive the loan: the total project cost, the loan-to-cost percentage set for your project, and the finished value. Terms are set per project after we review plans, budget, permits and the builder.
Your equity covers the gap between the loan and total cost. On San Diego projects, soft costs and site work often run higher than investors expect, so a complete budget gives you a more accurate loan amount from the start.
This example is illustrative and not a quote. An investor builds a main home and two detached ADUs in City Heights to hold as rentals. Land costs $850,000, hard costs are $1,150,000, soft costs are $200,000 and the contingency is $80,000, for a total project cost of $2,280,000.
At a sample 75% loan-to-cost, the loan is $1,710,000 and the investor puts $570,000 into the project. Most of the loan funds through draws as work is completed.
Once the main home and two ADUs lease for a combined $9,400 a month and the property appraises at $2,600,000, a DSCR refinance at 75% LTV would be $1,950,000, enough to repay the $1,710,000 construction balance. The rent then has to cover the new payment, including taxes and insurance, at the program's DSCR minimum.
| Item | Amount |
|---|---|
| Land | $850,000 |
| Hard construction costs | $1,150,000 |
| Soft costs (plans, engineering, permits, fees) | $200,000 |
| Contingency | $80,000 |
| Total project cost | $2,280,000 |
| Loan at a sample 75% LTC | $1,710,000 |
| Investor cash in the project | $570,000 |
| Monthly rent at completion | $9,400 |
| Completed value | $2,600,000 |
| DSCR refinance at 75% LTV | $1,950,000 |
Funds are released through a draw schedule, not in one lump sum. You finish a stage of work, request a draw, an inspector confirms the work in place, and the funds for that stage are released.
Build the schedule around how your San Diego builder actually sequences the job. Our construction draw schedule calculator can help you map stages to dollars before you apply.
We look for investors with a buildable plan and the team to execute it. Experience can be your own or your general contractor's. Projects without plans or permits, or with no build track record and no experienced general contractor, usually do not qualify.
We also look at the land. Owning the lot, or having it under contract with a clear closing date, along with a survey and any soils work, makes the San Diego file faster to review and the budget easier to confirm.
Decide the exit before you close. A sale exit should be supported by recent new-build sales nearby. A rental exit should be supported by local rents that can carry a DSCR loan at the 1.0x standard minimum, with sub-1.0 programs available in some cases.
If the finished property needs more time, a short-term bridge loan can sometimes fill the gap before the sale or long-term refinance.
Our investor loans are business-purpose loans on non-owner-occupied property. For your San Diego project, share plans, budget and land details through the form below, or call (877) 298-1001.
Often, yes, under state law and San Diego's rules, though the city has changed its ADU bonus program over time. Confirm the current limits for your lot and zone before you buy.
It affects the timeline. Lots in the coastal zone may need a coastal development permit, and lenders generally want approvals in hand before construction funding.
Yes. Once leased, the combined rent from the main home and ADUs can support a DSCR loan, with 30-year terms available.
It can. Fire hazard zones may require ignition-resistant construction, and insurance on the finished property may cost more. Both affect the project and the long-term rental math.
Yes. Small 5-8 unit buildings are part of our residential construction program. Buildings of 9 or more units are commercial.
Draws are tied to the approved budget, so overruns beyond the contingency generally have to be covered by the borrower. A realistic budget and contingency protect the project.
Usually only with an experienced general contractor on the project. A borrower with no build track record and no experienced GC usually does not qualify.
Loan-to-cost is the loan divided by the total project cost, including land, hard costs, soft costs and contingency. Construction loans are sized this way, with terms set per project.
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