Most unpermitted work in California is not discovered when it is built. It is discovered years later: when a neighbor complains, when an insurance claim is filed, when the house is sold, or when the owner applies for a permit for something else and an inspector notices a bedroom that was a garage on the last set of plans.
By then the person paying for it is often not the person who did it. Here is what happens when unpermitted construction comes to light in California, what it costs to fix, and how to legalize it.
Do You Need a Permit?
For most work that changes a structure or its systems, yes. California requires a building permit for new construction, additions, structural changes, changes of use (such as converting a garage into living space), and most electrical, plumbing and mechanical work. A small set of minor projects are exempt, such as painting, flooring and some small accessory structures, but the exemptions are narrow and vary by jurisdiction.
If you are unsure whether a project needs one, our guide to California building permit requirements covers the common cases.
What Happens If You’re Caught Building Without a Permit
The consequences escalate depending on how the work is discovered and what was built.
- Stop-work order. If work is discovered in progress, the building department can order it stopped until a permit is issued.
- Higher fees. Many California jurisdictions charge an investigation fee on top of the regular permit fee when work starts without a permit, often equal to the permit fee itself. You pay to permit the work and then some.
- A recorded notice of violation. In Monterey County, an unresolved code violation can be recorded against the property. Clearing it requires resolving the violation and paying the county’s administrative costs and recording fees.
- Opening up finished work. Inspectors need to see what is inside the walls: framing, wiring, plumbing, insulation. On finished work that can mean removing drywall or flooring so it can be inspected.
- Removal. If the work cannot be brought to code, or it violates zoning (setbacks, height, lot coverage), the remedy may be demolition.
Work legalized after the fact is generally reviewed against the code in force when you apply, not when it was built. For a project discovered today, that is the 2025 California Building Standards Code, effective January 1, 2026, which may require more than the original work provided.
What Unpermitted Work Does When You Sell
This is where most owners feel it. California sellers of residential property must complete a Transfer Disclosure Statement, and it asks directly about room additions, structural modifications or other alterations made without necessary permits. Unpermitted work you know about has to be disclosed.
Once disclosed, it affects the sale in several ways:
- Value. Appraisers and lenders frequently give unpermitted living space no value, so the square footage you paid to build may not count.
- Financing. A buyer’s lender may require the work to be legalized or removed before closing.
- Negotiation. Buyers discount for the cost and uncertainty of legalizing, and the discount is usually larger than the cost of having permitted the work in the first place.
Unpermitted work can also complicate insurance claims if the damage involves that work, and if it is discovered it can be added to the property tax roll retroactively. We cover the tax side in does an ADU increase property taxes.
Unpermitted ADUs: The AB 2533 Exception
Unpermitted ADUs get special treatment. Under AB 2533, effective January 1, 2025, an ADU or junior ADU built before January 1, 2020 can be legalized without being held to every current building standard, as long as it does not present a serious threat to health and safety. Local agencies cannot deny the permit simply because the unit was built without one.
The exception is specific. It does not cover:
- ADUs built on or after January 1, 2020
- Garage conversions, additions or remodels that are not ADUs
- Units with genuine life-safety hazards, which still have to be corrected
If you have an older unit that could qualify, it is worth pursuing. Legalizing it can restore the value an unpermitted unit loses, as covered in how much value an ADU adds. For how the current ADU rules fit together, see California ADU law in 2026.
How to Legalize Unpermitted Work
The path is the same whether you are fixing work you did, work a previous owner did, or a problem a buyer’s inspection turned up.
- Document what is there. The building department needs drawings of the work as it actually exists. These are as-built drawings: measured plans, elevations and details of the existing structure.
- Find out what it needs. Compare what was built against current code and zoning. Some work needs nothing more than inspection; some needs upgrades such as egress windows, insulation, fire separation or structural reinforcement.
- Apply for the permit. Submit the as-built drawings, plus drawings of any corrections, for plan review. Expect investigation fees if your jurisdiction charges them.
- Open up and inspect. The inspector will need access to concealed work. Plan for limited, targeted openings rather than tearing everything out.
- Correct and finalize. Make any required corrections, pass final inspection, and the work is legal. Keep the finaled permit with your property records.
In Monterey County, after-the-fact permits are possible, but what can be legalized depends on the size of the work and the zoning. Calling the county planning department before you start is free and can save a wasted application.
If You’re Planning Work Now
The cheapest permit is the one you get before construction. It costs less than an after-the-fact permit, avoids opening finished walls, protects the value of what you build and keeps your next sale clean. The drawings are usually the part that stops people, and that is the part we do.
Renovation Drafting & Design prepares permit drawings for new work and as-built drawings for legalizing existing work across Monterey, Carmel, Pacific Grove, Pebble Beach and Carmel Valley. Contact us with what you have, and we’ll tell you where to start.
This article is general information, not legal advice. Enforcement practices and fees vary by jurisdiction; confirm specifics with your local building department.
Building Without a Permit FAQs
What happens if you build without a permit in California?
If discovered, the building department can issue a stop-work order, charge investigation fees on top of the permit fee, record a notice of violation against the property, require finished work to be opened for inspection, and in some cases require the work to be removed. Unpermitted work must also be disclosed when the property is sold.
Can unpermitted work be legalized in California?
Often, yes. The usual process is to prepare as-built drawings of the existing work, apply for a permit, open concealed work for inspection, and make any corrections required by current code. Work that violates zoning, such as setbacks or height limits, may not be legalizable.
Do I have to disclose unpermitted work when selling a house in California?
Yes. The California Transfer Disclosure Statement asks sellers about room additions, structural modifications or other alterations made without necessary permits. Known unpermitted work must be disclosed.
What is AB 2533?
AB 2533, effective January 1, 2025, creates a path to legalize ADUs and junior ADUs built before January 1, 2020. Local agencies cannot deny a permit for such a unit solely because it was built without one, provided it does not present a serious threat to health and safety. It does not apply to non-ADU work.
Is there a penalty fee for building without a permit?
Many California jurisdictions charge an investigation fee when work begins without a permit, often equal to the permit fee. In Monterey County, a recorded violation also carries administrative costs and recording fees to clear. Fees vary by jurisdiction.
Can a building inspector make me tear out unpermitted work?
Yes, if the work cannot be brought into compliance with the building code or violates zoning. In many cases work can be corrected and permitted instead, but removal is a possible outcome.