Mailbox Keys Not Working (USPS Explained)

Mailbox keys are small and quite easy to lose them. Even if you didn’t lose them there is a high chance they might be sticking inside the mailbox lock, critically bending, and eventually breaking inside the mailbox cylinder. There are two types of mailbox ownership such as private mailbox and United States Postal Service which is government owned.

Mailbox keys might stop working for several reasons. Because mailbox locks can be affected by the weather such as lock can become too dry to turn the key properly – so try to lubricate it with WD40 lubricant. Second, someone tried to mess with your mailbox lock. There are tons of mailbox theft happening nowadays. Last but not least, someone changed a lock without you knowing it, or maybe the wrong set of keys.

While the above list is a top possible scenario, there are more reasons that can trigger mailbox lock issues such as the right key still won’t unlock the mailbox door, so you can try to shake, push and pull the door since it might be a pressure affecting the tailpiece that keeps the door tight.

Or quite a rare one, but the key cut (3-5 sharp mountains & hollows along the key shaft) is worn out. When key cuts are worn out, it might change structure just a tiny bit which is crucial for a cylinder that can associate that key as a foreign key.

What is the difference between private and USPS mailboxes?

Private mailboxes are owned by owners. It might be any type of housing such as townhouses, single-family houses, or apartments. Typically in this type of case, mailboxes have various designs, shapes, and colors. Unlike USPS, which generally (not always) has a plain and simple silver color big box that has a bunch of small cells.

It is hard to say why some places are controlled by USPS and some are not. To find out exactly your mailbox status you should ask your leasing office, hoa, landlord, or contact the local USPS office.

If the mailbox needs maintenance support you should keep in mind that if the mailbox is owned and maintained by the United States Postal Service then breaking into it is a federal offense. You should request the local office to replace the lock and someone from the office will install a new lock for you for a small fee. You may not break into it even if it is on your property.

If you own the box, you can break into it and change the lock at your own expense. First, you can try to do it yourself by applying proper drilling techniques and eventually replacing the lock with a new home depot mailbox lock

Does USPS change mailbox locks?

Yes, USPS local office will replace the mailbox and you will have to pay for that service. The only HUGE issue is that it takes a long time until they come and change it. What if you have some urgent mails in the locked mailbox?

Then you might want to ask a locksmith to unlock it for you without damaging or changing the lock. Moreover, ask usps office to keep future mails in the local office so that you can pick them up from the window until the mailbox lock is replaced by their field tech

Current standards require payment of the lock replacement fee when a customer requests that the lock be changed. The Postal Service also applies this fee when customers renew PO Box™ service more than 10 days after the renewal due date. This provides an incentive for customers to pay their PO Box rental fee on time.

How much is it to replace a mailbox key at USPS?

Typically prices can vary from place to place. Generally, USPS does not charge a lot, unlike locksmith professionals. You should expect between $30-60 for labor and parts for the replacement provided by USPS field staff.

Is it illegal to open someone else’s mailbox to put something in?

Absolutely illegal. You can’t unlock someone’s mailbox or ask mail delivery staff.

Can I replace my own mailbox lock?

Yes as long as it’s your own mailbox you can do it yourself or call a locksmith which might cost between 95-250 depending on the region and locksmith company itself.

In case you live in an apartment complex or rental property and wonder if you can change your door lock? Here is everything you need to know about that case

Does USPS have a copy of my mailbox lock?

No, USPS doesn’t have a key for your particular mailbox. They have a key for a whole door panel that has access to dozens of small cells. If you lost the key, the USPS office can’t give you a copy of the lost key since they don’t have it from the beginning. You will have to ask them to replace a lock that already comes with 2 sets of keys. Later you can try to make copies of those provided keys.


I am Rauan, I have over 4 years of experience as a locksmith tech and then as the owner of my own company. I live in Houston, TX, and love to provide valuable insights related to locks. Enjoy reading

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