Approval delays add more than $75,000 to the cost of building a typical new single-family home in California. The calculation below uses an average construction cost of $400 per square foot, an average new-home size of 2,401 square feet (the U.S. Census Bureau’s Western U.S. average), and the 8% increase in total development costs that California’s extended development timelines cause. Prop 45 sets enforceable deadlines for agency decisions and court challenges to cut those delays.
How the $75,000 figure is calculated
| Item | Amount | Source / calculation |
|---|---|---|
| Average cost per sq ft in CA | $400 / sq ft | HomeLight, The Cost to Build a House in California (2025): “In California, the cost of building a home can start at $400 or more per square foot.” |
| Average home size, Western U.S. (new construction) | 2,401 sq ft | U.S. Census Bureau, Characteristics of New Housing (2025): average size of new single-family home in Western U.S. ≈ 2,401 sq ft. |
| Base development cost | $960,400 | $400 × 2,401 sq ft |
| Average delay impact | 8% increase | California YIMBY Education Fund (2024): “California’s extended development timelines directly increase total development costs by about 8%, or $1,284 per unit per month of delay.” |
| Added cost from delays | $76,832 | $960,400 × 0.08 |
The calculation comes to $76,832 per home. We round it down and say “more than $75,000” to keep the figure conservative.
Sources
- HomeLight, “The Cost to Build a House in California” (2025)
- U.S. Census Bureau, “Characteristics of New Housing” (2025)
- California YIMBY Education Fund, “Why Housing Costs More in California Than Colorado or Texas” (2024)
About this estimate
This is an estimate for a typical new single-family home, not a specific project. Actual costs vary by location, home size and the length of the delay. Analysis by Yes on 45 using the public data sources listed above.