In order to get the best postage discount, Fairfax County participates in an address update process with the United States Postal Service (USPS) for our real estate assessment notices and real estate tax bills. Changes in address that are reported to the Post Office are updated to our system quarterly. If you would like to opt out of this automated process for your mailing address, use the Property Account Inquiry form and select the "Opt Out of USPS Address Changes" option in the Reason for Inquiry field.