What is the 30% rule for renovations in California?
Many homeowners hear about a “30% rule” for renovations. It is not a law. It is a planning idea that says you might spend around 30% of your home’s value on a full renovation. In California, costs vary by city, permits, and materials. Use this rule only as a starting point.
How to use the 30% idea
Use it to set a rough cap before you get quotes.
Compare it with current price per square foot in your area.
Adjust for scope. Kitchens and baths can push costs higher.
When the rule fails
Historic homes or major structural changes.
High-end finishes or custom work.
Hidden problems like old wiring or water damage.
Better planning steps
List must-haves and nice-to-haves.
Get at least two detailed quotes.
Add a 10–20% contingency for surprises.
Confirm permit needs and timelines with your city.
Use 30% as a rough guide only. Real budgets in California depend on scope, codes, and materials. Clear plans and detailed quotes lead to better outcomes.
