Knob-and-Tube: Insurance and Selling in California (2026)

No California law forces you to replace knob-and-tube wiring to sell a house, but the state's Transfer Disclosure Statement asks sellers about known significant defects in the electrical system, and brokers in a 2025 ABC7 San Francisco report said many insurers decline or nonrenew homes that have it. Insurers decide case by case and policies vary. Replacement typically runs $8 to $17 per square foot, based on HomeGuide's 2026 national figures. VoltGen Energy's advice to Los Angeles homeowners: get the wiring evaluated in writing, ask your insurer what it needs to see, and talk to your agent about the disclosure before deciding what work to do.

Will home insurance cover a house with knob-and-tube?

Coverage may be available, but you should not assume an insurer will accept knob-and-tube or renew an existing policy. Ask your agent about the specific property and policy before relying on coverage for a purchase or deciding to postpone replacement.

A 2025 ABC7 San Francisco report described brokers seeing homes declined or nonrenewed because of knob-and-tube wiring. One broker said, "If we put it on the application, we are going to get declined." The report also described some owners ending up on the California FAIR Plan.

There is another important part of that report: the San Francisco Fire Department said it "has not seen trends in knob and tube electrical wiring residential structure fires." That statement does not establish the condition of your home's wiring or determine an insurer's decision. An underwriting concern and an evaluation of a particular electrical system are different questions.

Ask your agent what documentation the insurer needs. That might include a written electrical evaluation, proof of replacement, or a permit sign-off. Do not assume that submitting any particular document guarantees acceptance.

If you receive a nonrenewal notice, check the dates. Under California Insurance Code 678, for policies expiring on or after July 1, 2020, an insurer that will not renew must send written notice at least 75 days before expiration. If it fails to do so, the policy remains in effect for 75 days from when the notice is delivered or mailed.

The California FAIR Plan is the state's insurer of last resort for basic property coverage when the regular market will not write a home. Ask an agent what coverage would apply and what it would leave out. For help with an insurance question or notice, contact the California Department of Insurance at 800-927-4357 or insurance.ca.gov.

Do I have to replace or disclose it when selling?

Replacement is not required by a California statute simply because you are selling, but the disclosure form asks about known significant defects in the electrical system. A buyer's lender or insurer may impose its own conditions, separate from the seller's disclosure duties.

California Civil Code 1102 requires a Real Estate Transfer Disclosure Statement, or TDS, for most home sales. The form appears in Civil Code 1102.6. Section II.B asks whether the seller knows of significant defects or malfunctions and specifically lists "Electrical Systems."

Section II.C also asks about alterations or repairs made without necessary permits and work that is not in compliance with building codes. If you know about wiring problems, unpermitted alterations or an earlier contractor's findings, discuss those facts when preparing the disclosure. Do not assume that selling without repairs removes your disclosure duties.

Buyers' inspectors commonly note knob-and-tube wiring. Sharing an existing evaluation and available permit records can help everyone understand what is known, what remains uncertain and what a proposed repair would cover.

Before agreeing to a repair credit or replacement deadline, ask the buyer's side to clarify any lender or insurance conditions. A credit does not necessarily satisfy those conditions. Talk to your agent or a real estate attorney about your disclosure; this guide is not legal advice.

Can I blow insulation around knob-and-tube in California?

Not without addressing the wiring and California's specific exception requirements first. Do not authorize an insulation crew to cover concealed knob-and-tube based only on a visual check or a verbal assurance.

Section 394.12(5) of the California Electrical Code, based on the NEC, prohibits concealed knob-and-tube in hollow wall, ceiling and attic spaces where loose, rolled or foamed-in-place insulation envelops the conductors. Knob-and-tube also has no equipment ground: its two wires are hot and neutral.

California adds an insulation exception, quoted on the City of Berkeley's knob-and-tube wiring form. It requires all of the following:

• A California-licensed electrical contractor surveys the wiring and states in writing that it is in good condition, with no deterioration, proper overcurrent protection and no improper connections or splices.
• That signed statement is filed with the building department, and the owner receives a copy.
• The insulated areas have a caution notice in English and Spanish.
• The insulation is noncombustible as defined in the California Building Code.
• The insulation contains no electrically conductive material.

That is not a blanket approval for blown-in insulation. Ask your local building department how it handles the exception before scheduling work. Repairs, alterations or extensions require permits and inspections, and your city may require an insulation permit too. Keep the signed statement and any final permit documents with your house records. Your inspector has the final say.

What does knob-and-tube replacement typically cost?

HomeGuide's 2026 national figures put replacement at $8 to $17 per square foot. Treat that as a planning range, not a Los Angeles quote or a prediction of the work your house needs.

These are typical market ranges, not our prices.

HomeGuide's 2026 national figures list lath-and-plaster repair separately at $50 to $125 per square foot. Ask how much surface repair the quote allows for and whether patching and painting are included. Do not apply a wall-repair rate to the home's entire floor area without a defined repair scope.

HomeGuide estimates about 3 to 10 or more days of wiring work, plus time for permits, inspections and wall repair. Do not use the wiring-work estimate alone to set a closing deadline.

For more budgeting context, read the knob-and-tube replacement cost guide and whole-house rewiring cost guide.

What should my quote include, and who handles permits?

Ask for a written scope that explains what wiring will be replaced, what will remain and who handles permits and repairs. A quote for limited work is not directly comparable to a whole-house replacement proposal.

Useful questions include:

• What evaluation supports the proposed replacement scope?
• Will any active knob-and-tube remain after the work?
• Who handles access openings, plaster repair and painting?
• Who obtains the permit and coordinates inspections?
• What completion records will I receive?
• Does the proposed scope address the insurer's written requirements?

For an older house, compare the proposal with your broader old home rewiring plans. Tell the contractor about planned insulation or remodeling so the scope addresses those plans rather than treating each job separately.

Replacement is permitted work under the California Electrical Code, based on the NEC. Inside the City of Los Angeles, including Studio City, the permitting agency is LADBS. In Burbank, Glendale or Pasadena, contact the respective city's Building and Safety department. Request the final permit documents when the work is complete. Your inspector has the final say.

Getting an estimate

VoltGen Energy serves Burbank, Glendale, Pasadena, Studio City and Los Angeles. For knob-and-tube replacement, share any electrical reports, insurance requirements and sale or insulation plans when you request a quote.

VoltGen Energy operates under Akopi Builders, CSLB #1112420. Electrical work is performed by licensed C-10 electrical contractors.