Case Study: Maximizing Rental Income with a 2-Bed ADU

Building an Accessory Dwelling Unit isn't just about constructing a guest house for aging parents; in San Diego County, it represents one of the most powerful, high-yield cash-flowing real estate investments accessible to middle-class homeowners.

The Scenario: Poway, California

Our clients possessed a sprawling, 0.4-acre lot in Poway with a vastly underutilized rear grass yard. Facing rising costs of living and wishing to establish passive income for retirement, they contracted CRS Builders to design and construct a fully detached, 850-square-foot, 2-bedroom, 2-bathroom ADU.

The Financial Breakdown

Financing the construction was achieved via a Home Equity Line of Credit (HELOC), leveraging the explosive appreciation their primary home had experienced over the last five years. The total cost of the project—from architectural design and grading to the premium appliances and final paint—came in at roughly $245,000.

At a blended borrowing rate of roughly 7.5%, the amortized monthly debt service on the construction cost hovered around $1,700 per month. But here is where the power of the San Diego rental market takes over.

The Cash Flow Reality

Because the unit featured two bedrooms, two full luxury bathrooms, an in-unit washer/dryer, and a dedicated patio space, it was highly appealing to young professional couples and small families priced out of the traditional single-family home market. Upon receiving the Certificate of Occupancy, the unit was leased immediately for $3,200 per month.

The Infinite Return

Not only did the ADU generate $15,000 in pure, net-positive cash flow in its first year, but the appraisal value of the primary property skyrocketed. The new 850 square feet of permitted, habitable luxury living space added an estimated $400,000 to the total property valuation, immediately securing the clients a massive net-worth increase that far exceeded the construction debt.