If someone enters an invalid apartment, will that be explained in the data returned? For instance: if a building has apartments with letters A-K, and someone enters in an address with "apt #5," will your system indicate that something is wrong?
First, a little background on how and when the USPS stores apartment information. Think of an apartment building like a business. You have the lobby and then you have additional internal addresses (the apartments). The building, with the lobby, doesn't change but the apartments will certainly change tenants, and even two apartments might remodel to combine to make one larger apartment. That's all fine, but how does the USPS handle that?
Because their goal is to deliver mail as quickly as possible without errors, they want to keep a list of as many internal addresses as possible. However, it is up to the building owners to submit any changes to the internal addresses. So, for the most part, the USPS knows what apartments exist within an apartment building. They even keep track of which ones are vacant and when the vacant status changes. The system does work pretty well. However, it is not a perfect system, and there are many variables to consider. The final choice is up to the building owner. Sometimes building owners make changes without informing the USPS.
To check an address now, you can try entering it into our system.
Example: The top floor of an apartment building burns down and they decide to clean it up but not to rebuild it. It may take months (or even years) before they remember to inform the USPS about that those apartments no longer exist.
Some apartments operate more like a nice hotel, meaning that all mail is received at the lobby. Thus, they don't submit apartment number information to the USPS. Certainly their tenants will give out the apartment number as their mailing address but the mail will all be delivered to the lobby. In cases like that, the USPS sees that building as only one address. It will be listed in the database as a "highrise" but will not have internal address data.
So, most highrises (and other such buildings) do submit their internal address data to the USPS, but as you can see, there are alternate cases.
The best way to check exactly what our output will be for a given case is to just try it out on our website.
If you enter an address with a valid apartment number, you get this:
dpv_match_code of "Y" means that the address is valid including the apartment/suite information. A
dpv_footnote of "AABB" means that the address, as entered, is an exact match within the USPS database of valid addresses.)
If you enter an address with an invalid apartment number, you get this:
dpv_match_code of "S" means that we were unable to verify the address WITH the secondary number (suite or apartment info) and so it reverted back to the default address without the secondary number. A
dpv_footnoteof "CC" means that we had to drop the secondary information in order to get a match. The apartment number may have been incorrect OR the USPS doesn't store the apartment numbers for that address in their database.)
If you enter an address with a missing apartment number (when it should have an apartment number), you get this:
dpv_match_code of "D" means that the system knows that there should be additional secondary information (suite or apartment) but even lacking that secondary data we were still able to verify the default location. A
dpv_footnote of "N1" means that there should be secondary information but it is missing so in order to get a match, the default address was used.
You will need to interpret those results and generate an appropriate response for your customer (depending on your needs), perhaps indicating that an apartment number is probably missing (since it is listed as probably having an apartment number). Remember, however, that each apartment building has a valid lobby address AND apartment addresses. To say that an address in a highrise is invalid just because it doesn't have an apartment number would not be completely precise because the lobby is valid as well. Just keep that in mind.