LA County Property Tax Deadlines Business Owners Can't Miss

If you own a storefront, an office building, a warehouse or a few rental units in Los Angeles County, two property tax deadlines are coming. One is about paying. The other is your yearly chance to argue that your assessment is too high. Both fall within the next six weeks.

Dec. 10: the first installment deadline

The Los Angeles County Treasurer and Tax Collector said it would mail about 2.4 million 2026-27 annual secured property tax bills on or before Nov. 1, according to its October press release. The first installment was due Nov. 1 and becomes delinquent after close of business on Thursday, Dec. 10, 2026. The second installment is due Feb. 1, 2027, and becomes delinquent after close of business on Monday, April 12, 2027, because April 10 falls on a Saturday.

A late installment carries a 10% penalty, and a late second installment adds a $10 cost.

A few points that trip up business owners:

• Not getting the bill is not an excuse. The county says state law does not relieve owners of the duty to pay on time if a bill never arrives. If you recently bought a property, changed your mailing address or hold title through an LLC, check your parcel on the county's property tax portal instead of waiting for mail.
• Postmarks matter. Mailed payments count only if the U.S. Postal Service postmarks them by the delinquency date. The county's penalty cancellation guidance warns that office postage meters, pre-canceled stamps and bank bill-pay services usually don't produce a postmark. It also says the county will deny penalty relief requests based on bill-pay timing. If you mail a check, ask for a dated label at a USPS retail counter.
• Online payments work until 11:59 p.m. Pacific on the delinquency date, by eCheck or card.
• Check your lender's escrow. If your commercial mortgage has an impound account, confirm that the lender has the right parcel numbers and actually paid.

Nov. 30: the deadline to challenge your assessed value

The less familiar deadline may matter more. Under Proposition 13, a property's assessed value can rise by no more than 2% a year. But under Proposition 8, when a property's market value falls below its assessed value as of Jan. 1, the owner can seek a temporary reduction.

The county gives owners two routes, and both close on Monday, Nov. 30, 2026:

1. Decline-in-Value Review. This is an informal request to the Los Angeles County Assessor using Form RP-87. The filing period runs July 2 through Nov. 30. The Assessor's office says the best support is two sales of comparable properties that closed as close to Jan. 1 as possible, and no later than March 31. Applications without comparable sales are still accepted.
2. Formal appeal. You can file an appeal with the Assessment Appeals Board, which says its 2026 regular filing period ends Nov. 30 at midnight Pacific. Each application carries a $46 non-refundable fee, and hardship waivers are available. The board accepts appeals on both real property and business personal property assessments.

The Assessor's office says you can file a formal appeal without waiting for an answer on an informal review. Doing so protects your right to appeal if the review does not go your way. For a business owner, filing both by Nov. 30 is often the safer path.

Who should take a hard look this year

You don't need a falling market everywhere. You need evidence that your property was worth less than its assessed value on Jan. 1, 2026. Candidates include:

• Owners who bought or built at a recent peak, whose base-year value may now sit above what similar buildings sell for.
• Owners of older office or retail space in areas with high vacancies, where recent sales of comparable buildings have been weak.

Keep in mind that a Prop 8 reduction is temporary. The Assessor's office notes that when values recover, the assessed value can rise faster than 2% a year until it reaches the original trended base value again.

If you are a tenant, not an owner

Many LA small businesses lease space under triple-net or similar leases that pass property taxes through to tenants. If that describes you, these deadlines still affect your costs. Ask your landlord or property manager whether they have reviewed the assessment this year. A successful appeal by the owner can lower what you pay.

Fire-affected properties

Owners whose property was damaged in the January 2025 Eaton and Palisades fires have separate relief options. The county's penalty cancellation form lists natural disasters, including wildfires, as circumstances that may qualify. The Assessor's disaster relief page explains how to apply for a misfortune and calamity reassessment.

The short checklist

• Confirm every parcel you own and the amount due on the county portal.
• Pay the first installment by Dec. 10. Pay online or mail early with a dated USPS label.
• Pull recent comparable sales and decide by Nov. 30 whether to file an RP-87 review, a formal appeal or both.
• Tenants: ask your landlord what they are doing about the assessment.

Rules and fees can change, so check the county's official pages or a property tax professional before you file.