Replacement Cost Coverage and the Time Limits That Apply
Replacement cost is the cost to repair, rebuild or replace what was lost without a deduction for depreciation. Actual cash value is, in plain terms, a lower measure that accounts for depreciation; California Insurance Code § 2051.5 refers to section 2051 for its definition.
Under § 2051.5(a), when a policy requires payment of replacement cost, the measure of indemnity is the amount it would cost the insured to repair, rebuild or replace the thing lost, without deduction for physical depreciation, or the policy limit, whichever is less. That last clause is why underinsurance matters so much: replacement cost coverage still stops at the limit.
If the policy requires the home to be rebuilt before full replacement cost is paid, the insurer pays actual cash value until the property is repaired, rebuilt or replaced, and then pays the difference between that payment and the full replacement cost reasonably paid, up to the policy limits.
Under § 2051.5(b), a policy generally may not give an insured less than 12 months from the date of the first actual cash value payment to collect full replacement cost, subject to the policy limit. For a loss relating to a state of emergency, the minimum is 36 months from that same first payment, again subject to the policy limit. The statute does not prohibit an insurer from allowing more time.
These periods run from the first payment, not from the fire, and the stake for you is the difference between actual cash value and full replacement cost: a policy's deadline to collect that difference can come up while rebuilding is still underway. Homeowners often keep a record of when that first payment arrived, any written grant of more time, and contractor bids showing the real cost to rebuild. The three-year wildfire claim timeline for other claims is a separate rule.