Address VerificationDirect Mail

What Does Not Deliverable As Addressed Mean

By 14 February 2024April 15th, 2024No Comments
not deliverable as addressed

What Does Not Deliverable As Addressed Mean

If you or your company regularly sends out postal mail, then you will surely have had instances when the mails were returned to you. Return mails are a clear indication that your direct mail process is not optimized. More often than not, postal return mails are the result of bad data in your address database. When postal mail gets returned, the mail carrier cites a reason why they could not deliver it. The most common reason cited by the mails carriers is “Undeliverable As Addressed”, also called UAA. And at this point, you’d have surely wondered, “What does not deliverable as addressed mean?”

not deliverable as addressed

If postal mail is classified as UAA or Undeliverable As Addressed, it means that mail did not reach its intended destination due to the address being incorrect, incomplete, or illegible. The UAA mails can become a costly issue not just for your business but also for your postal service provider. It is estimated that postal services incur a net loss of $1.5 billion due to various reasons, including UAA.

Similarly, the mailing industry suffers a net loss of $20 billion. The losses due to UAA are wide and extensive; it includes losses due to returning, destroying, or forwarding undeliverable mails.

But you’d be wrong to think that that's the only loss caused by UAA mails because undelivered mails also mean that the mailers will have significant direct losses too. The direct losses that incur on mailers include printing and postage costs, which are further pushed by indirect losses such as lost opportunities.

This article discusses “Undeliverable As Addressed” or UAA mails and how they can affect your business’s direct mail efforts. Furthermore, we dive into the details of UAA and discuss the instances when a non-deliverable delivery address or mail can be considered as UAA and the reasons behind it.

Undeliverable As Addressed or UAA Mails

According to the USPS, Undeliverable As Addressed or UAA mails are all the mails that can not be delivered to the addressee or address specified on the mail piece. This mail must then be forwarded to the secondary address or returned to the Sender, and if that’s not possible, the mail must then be treated as waste.

As mentioned before, the UAA is possibly the biggest reason behind return mails and effectively the reason behind the huge losses that are incurred in the mailing industry every year. Thus UAA is the worst enemy for companies that rely on direct mail efforts.

Did you know that 17% of Americans change their address each year?

Among these, only 40% of them bother to report their address change to the USPS. This further underlines the effects that UAA can have on your company’s direct mail campaigns. If UAA goes unchecked, it can become disastrous for your business.

On the bright side, direct mails has evolved over the years, and it has grown to accommodate smart solutions to ensure maximum deliverability of direct mails. Today, we have access to superior address verification tools such as PostGrid that can help companies verify addresses in bulk to ensure their deliverability.

Also Read: International Address Verification Services

UAA Codes & The Reason Behind “Undeliverable As Addressed” Mails

According to the USPS, over 20 UAA codes may be displayed on the return mails, and each code is specifically assigned for each scenario where the address or mail is undeliverable. Now, some of these UAA codes are pretty self-explanatory and straightforward, while some others are more complex, which may seem confusing.

Below we list and explain all the major UAA codes that you need to be familiar with so you can understand why every direct mail you send was undelivered or returned to you.

Not Deliverable as Addressed/Unable to Forward

These are arguably the most common return mail you will come across. If the UAA code says that the mail is “Not Deliverable as Addressed” or “Unable to Forward”, it means that either the addressee of your direct mail has moved from that address or the data simply does not match with the address on the mailpiece.

Since the addressee has not applied for his/her postal mails to be forwarded to the new address, the USPS has no data on where the new address is nor any obligation to deliver it. In this case, the return code of 23 or 27 from CASS or NCOALink is used.

Insufficient Address

If the UAA code says “Insufficient Address”, then it means that the address you’ve written on the mailpiece is missing some crucial information. By saying crucial information, we mean the parts of the address without which the delivery simply can not be made. This could be a PO Box number, a missing city name or a nonexistent one, a street address without a number, an absent or nonexistent ZIP code, and so on.

No matter how good a mailing service you employ for your business’s direct mails, it simply cannot be delivered if the address is incomplete or without the necessary details. This kind of address can be identified by looking up a return code of 10-17 from CASS or NCOALink.

Attempted – Not Known

If you see the UAA code “Attempted – Not Known” on one of the return mails, it means that the addressee you mentioned on the mailpiece is not known or that they do not live at the address mentioned on the mailpiece. This is perhaps one of the toughest UAA codes to track before sending out the mail, even if you are using an advanced address verification tool. This is because neither NCOALink nor CASS can verify whether a specific addressee lives at a particular address.

Although it is possible to determine if a resident has moved from the given address, we can not determine if someone never lived there or newly moved there. In this case, the only way to ensure you have good address data is to get your data from a reliable source.

No Mail Receptacle

As the names suggest, this UAA code is used when a mailpiece does not have a mail receptacle acceptable to the USPS. Gated communities that use a mail center instead of the typical mailbox in front of each house are a perfect example.

Here, if you want to send mail to 1408 Walls Street, it can not be delivered directly to the address because they don’t have a mailbox. Instead, the mail has to be delivered to 1408 Walls Mail Center. Such cases are often flagged by the USPS with a phantom route CRRT of R777.

No Such Number

As you might have already guessed, this UAA code refers to the key numbers in an address. The number that is written on your mailpiece (as part of the address) may not exist for that street. This is one of the most common UAA issues as many of us often mix up numbers unintentionally but that's not necessarily the reason every time. Sometimes the number is outside for the specific street, and if that’s the case, then you’d receive the return code 21 from CASS.

Returned for Better Address

This is another popular UAA code where the address on your mailpiece is not enough for the USPS personnel to make the delivery. In most cases that fall under this category, there is usually a better address for the recipient or the location. Such addresses are indicated by assigning an Undesirable Return Code once it goes through CASS and NCOALink processing.

Also Read: USPS Returned Mail Codes


When writing the address on the mailpiece, you need to ensure that the font of the handwriting is easily readable. The mails you send are sorted either by a postal sorting machine or a USPS staff and sometimes by both. Hence it is important to maintain good readability of the address you write on the mailpiece. In order to do this, it is necessary for you to look at the label design and print so that you can choose a font that can be easily read by USPS.

Outside Delivery Limits

Sometimes the post office that handles the addressee’s mails may change, and the postal mail sent to the first post office no longer covers the address where the addressee lives. USPS regularly updates this data on a monthly basis. Therefore, it is quite possible that the Post Office that covers the address in question may have changed. This UAA issue can also arise if you write down the incorrect city name because, in some cases, even though the addressee’s residence may technically be located in a city, the postal mail is handled by a different Post Office.

Returned for Postage

The postages are pretty much the tickets for mailpieces for taking them from point A to point B. You can not expect your direct mail to be delivered if it does not have postage. No postage on your mailpiece or having no indication that the mailpiece previously had postage pasted on it would mean that your postal mail will be returned to you. A simple solution to avoid such circumstances would be to use printed indicia. However, it is also important to note that there is a chance that you may run into production issues that can halt indicia printing.

Also Read: What Happens if Certified Mail is Not Signed For

Moved, Left No Address

This UAA code is used when the addressee has moved from his/her existing address without filing a Change of Address form or COA. In such cases, the USPS is aware that the addressee does not live there anymore, but they, however, do not have the data on where to send the mail. You can use the Proprietary Change of Address or PCOA tool to get through such a situation as the person has most likely updated their address with the numerous businesses they interact with frequently.

Temporarily Away

Temporarily Away is a UAA code that is used when the addressee is not present at their residence but still considers the address to be his/her general residence. This also applies if the addressee’s temporary forwarding or holding mail order has expired. Such cases may be reported as a temporary move by NCOALink.


Sometimes the addressee may refuse to accept the mail or refuse to pay the additional postage charge they are due. Such instances or postal mails are clubbed under the UAA code “Refused.” You can avoid such instances by making sure that the posts you send out have sufficient postage pasted on them. However, that still can not stop the recipient from refusing the mail.


If the postal address in your mailpiece is currently not occupied by anyone, then the address is treated as “Vacant.” Such cases are flagged in the DPV vacant field, which is returned from CASS or NCOALink.

Box Closed – No Order

If a PO Box gets closed without leaving a forwarding address and postal mail is sent to the said PO Box, then this UAA code is used. This is normally seen in cases where the PO Box gets closed due to non-payment. Such mailpieces come with a return code of 26 from NCOALink.


Suppose postal mails are not removed from the receptacle in a timely fashion, the mail carrier may be prompted to pick it back up, and it will be marked as “Unclaimed”. In such cases, the mail is returned but the address is correct and is a result of poor data quality.

Also Read: How To Ensure Address Data Quality For Your Business?


This UAA code pretty much explains itself. It is used when the addressee is deceased. However, such addresses can be easily filtered out using an advanced address verification tool such as PostGrid, and then you remove those addresses from your database.

Returned to Sender due to Addressee’s Violation

Although there are numerous variations to this issue, broadly, we can say that this was when the addressee violated a postal order or rule, which in most cases involves false representation. For such a situation, there isn’t much you can do other than simply remove the address from your database to avoid future mailings to the addressee.

In Dispute

This usually happens when there is some kind of dispute or disagreement among the postal officials about the direct mails sent to a specific location. In most cases, the local authority has a reason not to deliver postal mails, but the case is yet to be confirmed and entered into the CASS system.

No Such Office in

If you come across this UAA code, then you should understand that the Post Office that should service the mailpiece does not exist. This is most likely the result of outdated labeling lists in the second month of its validity. It is also worth noting that at this point a different set of labeling lists will already be published.

State No Such Street

Another self-explanatory UAA code; is used when the street listed on the address does not exist. The return code used for this is 10 or 17 from CASS.

Also Read: Where to Write Return Address on Letter


There are numerous reasons for postal mail to be Undeliverable As Addressed (UAA). But broadly speaking, we can say that a mailpiece is Undeliverable As Addressed when the address provided on it is not accurate. For businesses to optimize their direct mail efforts, it is essential to understand in-depth the factors that lead to postal mail returns.

UAA codes can be extremely helpful when it comes to identifying the reasons why your direct mail is getting returned. This can be crucial in getting a comprehensive understanding of your target audience.

Now that we know what it means for a mailpiece to be “Undeliverable As Addressed” or UAA we have discussed almost all major UAA codes that you may come across. However, the easy one-step optimization solution is to use an advanced address lookup API system like PostGrid. Systems like PostGrid can help you easily optimize the direct mail efforts of your company. Furthermore, such a system can streamline your mailing process and even automate it for maximum accuracy.

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