January 12, 2026|By One Stop Builders
Building a 500 square foot ADU in California? Complete cost breakdown from $150,000-$250,000+ including permits, design, and construction.
A 500 square foot ADU is one of the most popular sizes—large enough for a comfortable one-bedroom, yet efficient to build. Here's what to expect in 2026.
500 Sq Ft ADU Cost Breakdown
Total cost typically ranges from $150,000 to $250,000 in San Diego, depending on design and site conditions.
Cost Per Square Foot
- Budget Build: $300-$350/sq ft = $150,000-$175,000
- Mid-Range: $350-$400/sq ft = $175,000-$200,000
- Premium: $400-$500/sq ft = $200,000-$250,000
What Affects Costs?
Site access, slope, utility distance, design complexity, and finish level all impact your final cost.
Rental Income Potential
A 500 sq ft one-bedroom ADU in San Diego can rent for $2,000-$3,500/month depending on location.
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