Here is a little-known (but very useful piece of information).

The US Postal Services has a team of people that handle address updates. This team is localized to different regions so that they generally are aware of local nuances. If you need to talk to the USPS about getting an address issue resolved simply go to this USPS AMS site and enter your zipcode to find the team that handles addresses in that area:

https://postalpro.usps.com/ppro-tools/address-management-sys...

If they don't answer, leave a message. They have helped me thousands of times in my last 14 years working with address validations.

The USPS has always been correct since I moved in. It’s been local records and the telcos that have been the problem.

And in this case the fire companies had no problem finding my house in spite of the incorrect information in town records. As you suggest the field people on the ground generally know what the ground truth is.

Amen! ZIP Codes (if referring to the US Postal Service) were only ever made for the purpose to sorting and delivering mail more efficiently. ZIP Codes serve the purposes of the US Postal Service, full stop. They don't respect any political or geographical boundaries - and they change at the whim of the USPS, as they were created and are maintained to suit their needs.

If used for other purposes they fall short.

Address parsing is actually very easy. Knowing when you got it right (or wrong), that's the hard part, and that's where address validation come in handy.

If you can start with a list of all the following, you've got a great start:

prefix abbreviations street names street types suffixes city names state names

Add to that all the possible misspellings and then factor in levenshtein and soundex to account for misspellings you didn't know about and you've got a pretty dang good address parser. Figure out how to do that lickety-split fast, and you've got gold.