Form ASSR-451, Change of Mailing Address, is the Los Angeles County Office of the Assessor form you complete when your mailing address is incorrect or has changed. It is one of the forms used for Los Angeles County property tax records, and it covers real property as well as business and unsecured property. On FillingPDF you can fill out the form online and download or print the completed PDF; the Assessor receives it by mail or email, as described below.
Last updated
What is ASSR-451?
Form ASSR-451, Change of Mailing Address, is the Los Angeles County Office of the Assessor form that a property owner signs to report that the mailing address on file is incorrect or has changed, and to give the Assessor the new address.
The form identifies the property and the owner, then gives the new address. For real property (single family residential, apartments, office and all commercial properties) you list each affected parcel by its Assessor's ID Number (AIN) and property address, and you may add the document number from the deed and the recording number or date if known. For business property and unsecured property only, you enter the Company No. or Assessment No. shown on the unsecured tax bill instead.
The new mailing address block asks for street address, city, state and postal code. The form also asks for the owner's daytime phone and email address, a mail recipient name or in-care-of (c/o) name if different, and an optional comments line. Fields marked with an asterisk on the form are required fields.
The form is printed with the revision Rev. 5/26. The Assessor lists it by its own number, ASSR-451, on its forms page, where it appears separately from ASSR-129, Property Data Change Request. The form itself says that only requests received from the owner whose name appears in the Assessor's records are accepted for processing.
Who needs to file ASSR-451?
The owner of record uses Form ASSR-451 when the mailing address the Assessor has for a property is incorrect or has changed. The form states that only requests received from the owner whose name appears in the Assessor's records will be accepted for processing, and that it must be signed in the name of the authorized individual submitting the request.
Extra paperwork applies in two situations, according to the form:
- The owner of record is a company, legal entity, estate or trust.
- The request is submitted by an agent of the owner, or similar representative.
In either case, additional supporting documentation is required to process the change. The Assessor publishes the list of required documents at https://assessor.lacounty.gov/homeowners/change-mailing-address.
The form covers both real property and business or unsecured property. Owners of real property list their parcels by AIN; owners of business or unsecured property enter the Company No. or Assessment No. from the unsecured tax bill. If you have several affected parcels, the form has space for five AIN entries.
When to file ASSR-451
Complete Form ASSR-451 when your mailing address is incorrect or has changed. The form prints no deadline and no filing window of its own, so there is no separate due date to track.
Because the change takes effect only after the Assessor processes it, send the form as soon as you know the address on file is wrong or out of date. If you need help before sending it, the Assessor lists a phone number and an email address on the form, shown under How to submit.
Documents you need
- Supporting documents listed on the Assessor's change-mailing-address page, only if the owner of record is a company, legal entity, estate or trust.
- Supporting documents listed on the Assessor's change-mailing-address page, only if the request is submitted by an agent of the owner or similar representative.
How to fill out ASSR-451
Choose your property type
Use the Real Property section for single family residential, apartments, office and all commercial properties. Use the Business Property and Unsecured Property Only section for business or unsecured property.
List each affected parcel
For real property, enter each Assessor's ID Number (AIN) and its property address (street address, city, state, postal code). The form has five AIN lines; list every parcel affected by the change.
Add deed information if known
Enter the Document Number from the deed and the Recording No./Recording Date if you know them. These entries are marked as known-only on the form.
Enter the Company No. or Assessment No.
For business or unsecured property only, enter the Company No./Assessment No. from the unsecured tax bill, whichever applies.
Enter the new mailing address
Fill in the required New Mailing Address: street address, city, state and postal code.
Provide owner phone and email
Enter the Property Owner's Daytime Phone and the Property Owner's Email Address. Both are marked with an asterisk as required fields.
Name a mail recipient if needed
In Mail Recipient Name/In Care Of (c/o), enter last and first name if mail should go to someone other than the owner. Use Additional Info./Comments for any other note.
Enter the owner's name
Fill in the required Owner's Name fields: last, first and middle, matching the name in the Assessor's records.
Sign and date the form
The Owner's Signature and Date are required. The form must be signed in the name of the authorized individual submitting the request.
Review and download the completed PDF
Check that every asterisked field is complete, then download or print the completed PDF from FillingPDF. Add supporting documents if the owner is an entity, estate or trust or an agent is submitting, and send it as described under How to submit.
How to submit ASSR-451
Form ASSR-451 is returned to the Los Angeles County Assessor by mail or by email.
- Mail: Los Angeles County Assessor, 500 W. Temple Street, Room 301, Los Angeles, CA 90012-2770.
- Email: [email protected].
The form must be signed and dated by the owner, or by the authorized individual submitting the request, before it is sent. If the owner of record is a company, legal entity, estate or trust, or if an agent submits the request, include the supporting documents listed at https://assessor.lacounty.gov/homeowners/change-mailing-address.
For help, call 213.974.3441, email [email protected] or visit https://assessor.lacounty.gov. Spanish-language help is available at 1.888.807.2111. The form prints no fee and no processing time. FillingPDF lets you fill out and download the PDF; submission follows the channels above.
Common mistakes to avoid
- Submitting the request without the owner's signature and date; the form must be signed in the name of the authorized individual submitting it.
- Sending a request from someone other than the owner whose name appears in the Assessor's records, which the Assessor does not accept for processing.
- Leaving out the supporting documents when the owner of record is a company, legal entity, estate or trust, or when an agent submits the request.
- Leaving blank a field marked with an asterisk, such as the new mailing address, daytime phone, email address, owner's name, signature or date.
- Entering a Company No./Assessment No. for real property, or an AIN for business or unsecured property; each section is for one property type.
- Omitting a parcel affected by the change instead of listing every affected AIN and its property address.
- Mailing the form to an address other than 500 W. Temple Street, Room 301, Los Angeles, CA 90012-2770, or emailing it to anything other than [email protected].
Frequently asked questions
What is Form ASSR-451 used for?
Form ASSR-451, Change of Mailing Address, is the Los Angeles County Assessor form you complete if your mailing address is incorrect or has changed. It covers real property and business or unsecured property, and it must be signed by the owner or authorized individual.
Who can submit a change of mailing address to the LA County Assessor?
Only requests received from the owner whose name appears in the Assessor's records are accepted for processing. The form must be signed in the name of the authorized individual submitting it. Entities, estates, trusts and agents must add supporting documents.
Where do I send Form ASSR-451?
Mail it to Los Angeles County Assessor, 500 W. Temple Street, Room 301, Los Angeles, CA 90012-2770, or email it to [email protected]. The form prints no other submission channel.
What extra documents do I need if the owner is a trust or company?
If the owner of record is a company, legal entity, estate or trust, or an agent submits the request, additional supporting documentation is required. The Assessor lists the documents at https://assessor.lacounty.gov/homeowners/change-mailing-address.
Can I fill out Form ASSR-451 online?
You can fill out the PDF online on FillingPDF and download or print it. FillingPDF is an independent service and does not send the form to the Assessor; you mail or email it yourself through the channels on the form.
Which fields on Form ASSR-451 are required?
The form marks required fields with an asterisk: New Mailing Address, Property Owner's Daytime Phone, Property Owner's Email Address, Owner's Name, and the Owner's Signature and Date. Complete all of them before sending.
Do I list an AIN or a Company No. on the form?
Real property owners list each affected parcel's Assessor's ID Number (AIN) and property address. Owners of business or unsecured property only enter the Company No./Assessment No. from the unsecured tax bill, whichever applies.
Who do I contact if I need help with the form?
Call the Assessor at 213.974.3441, email [email protected], or visit https://assessor.lacounty.gov. For Spanish-language help, the form lists 1.888.807.2111.
Ready to fill out ASSR-451?
Fill out ASSR-451 now