US Post Company Guide to Cluster Mailboxes: Ownership, Repairs, and Replacement Options

Cluster mailboxes, also known as Cluster Box Units (CBUs), have become the standard for modern mail delivery across residential neighborhoods, commercial developments, and multi-unit properties. They provide a centralized, efficient, and secure solution for mail and package distribution, but when damage occurs or maintenance is required, it’s not always clear who is responsible. 

At US Post Company, we specialize in USPS-approved cluster mailboxes and commercial mailbox solutions from trusted brands like Florence Corporation and Salsbury Industries. Below, we’ll help you understand ownership responsibilities, repair procedures, and what to do when your cluster mailbox is damaged or needs replacement.

Are Cluster Mailboxes Required?

Yes, cluster mailboxes are required in most new residential and commercial developments. The U.S. Postal Service (USPS) has made centralized delivery its preferred and often mandatory method for new construction projects. This means that instead of individual curbside mailboxes, new neighborhoods and multi-unit properties must install USPS-approved Cluster Box Units (CBUs).

When a CBU is installed, the local post office equips it with a secure USPS Arrow Lock. This lock allows postal carriers to open the entire unit during delivery, ensuring mail and packages are distributed safely. If a package is delivered, the carrier places a parcel locker key in the recipient’s mailbox. Once the package is retrieved, the key remains in the lock until the postal carrier removes it with their control key.

This system ensures efficient delivery, prevents theft, and helps streamline operations for both residents and postal workers. Cluster mailboxes also reduce postal costs and minimize delivery time, making them a win for communities and developers alike.

Are Cluster Mailboxes Owned by the USPS?

Ownership of a cluster mailbox depends on who installed it and under what conditions. In some cases, cluster mailboxes are owned by the USPS, but more often they are privately owned - typically by a homeowners association (HOA), property manager, developer, or municipality. 

If your cluster mailbox was installed by a developer during a construction project, the ownership typically transfers to the HOA or property management once the community is occupied. In contrast, mailboxes directly installed and maintained by the USPS remain USPS property. 

The best way to confirm ownership is to review your property documents, contact your HOA or developer, or call your local post office. They can verify whether USPS or a private entity manages the unit. Understanding ownership is crucial, as it determines who is responsible for repairs, key replacements, and long-term maintenance.

Who Is Responsible for Broken or Damaged Cluster Mailboxes?

The party responsible for repairing or replacing a damaged cluster mailbox depends entirely on ownership. In most residential communities, the responsibility falls on the property owner, HOA, or property manager. These entities must handle issues like vandalism, weather damage, or worn-out locks.

If your CBU is USPS-owned, the Postal Service will typically handle maintenance related to the Arrow Locks and master door locks, as these components are critical for postal security. However, USPS does not repair damage caused by vandalism or accidents on privately owned units. In those cases, it’s up to the property owner or management team to contact a mailbox supplier for replacement parts or new units. 

At US Post Company, we supply replacement parts and new CBUs that meet all USPS regulations. We also offer expert guidance to ensure your mailbox system remains compliant and secure after repair or replacement.

Is USPS Responsible for Apartment Mailboxes?

In most cases, no - apartment and multi-unit mailboxes are owned and maintained by the property management company or landlord. The USPS provides the delivery service but does not take responsibility for mailbox repair or replacement unless the mailbox is part of a USPS-owned unit.

If an apartment mailbox is damaged, property managers should arrange for prompt repair or replacement to maintain USPS compliance and prevent mail delivery interruptions. USPS will typically only handle repairs related to arrow locks or master door locks, but not structural or cosmetic issues.

When replacement is needed, property managers can choose from a range of USPS-approved options, such as Florence 1570 Series Cluster Box Units or Salsbury Heavy-Duty Aluminum CBUs, all available through US Post Company.

What Happens to Your Mail If the Mailbox Is Broken?

If your cluster mailbox is broken, vandalized, or otherwise unserviceable, your mail carrier will leave a notice explaining the issue. Afterward, your mail will be held at your local Post Office™ for up to two weeks at no charge. If repairs are delayed, you can request an extension for up to 30 additional days.

During this time, it’s important to act quickly to repair or replace your mailbox. The USPS requires that all mailboxes used for delivery remain secure and operational. Delays in fixing the issue can result in prolonged mail holds and potential delivery interruptions.

For a fast, compliant replacement, visit US Post Company’s cluster mailbox section or contact our customer service team. We offer USPS-approved CBUs, replacement locks, and accessories to get your mail delivery system back on track quickly.

How to Report a Broken Cluster Mailbox

If your CBU is damaged, the first step is determining ownership. For USPS-owned units, contact your local Post Office™ directly or call the Postal Inspection Service at 1-800-ASK-USPS (1-800-275-8777). Provide your location, the type of damage, and any relevant details so the USPS can inspect or repair the unit as needed.

For privately owned units, contact your HOA, property management company, or building maintenance department. They are responsible for coordinating repairs or ordering replacement parts. You can also reach out to US Post Company for professional guidance and pricing on USPS-approved replacement mailboxes.

Our experts can recommend durable replacement CBUs that match your existing setup, including options with multiple tenant compartments, parcel lockers, and pedestal-mounted configurations for outdoor installations.

How to Replace a Broken Cluster Mailbox

Replacing a broken or outdated cluster mailbox requires careful attention to USPS specifications. All replacements must meet USPS regulations depending on installation type. Choosing the right model ensures your mailbox remains compliant, secure, and long-lasting.

At US Post Company, we carry a full lineup of USPS-approved cluster box units, including:

• Florence 1570 Series CBUs - The industry standard for durability, reliability, and USPS compliance.
• Salsbury 3300 Series Cluster Box Units - Available in multiple door configurations and powder-coated finishes.
• Outdoor Parcel Lockers - Perfect for managing larger deliveries securely and efficiently.

Each unit is engineered for weather resistance, security, and compliance with all USPS centralized delivery requirements. Whether you’re managing a new development, apartment complex, or office park, our team can help you select the right mailbox system to meet your site’s needs.

Replacing your mailbox isn’t just about compliance, it’s about convenience, security, and peace of mind. By choosing a USPS-approved cluster mailbox from US Post Company, you ensure long-term reliability and a professional appearance for your property.

Get Expert Help with Cluster Mailboxes

Whether you’re a property manager, contractor, or developer, understanding who is responsible for cluster mailboxes can save you time, money, and frustration. If you need help determining ownership, selecting replacement parts, or upgrading your current setup, our team at US Post Company is here to help.

We carry the nation’s top-rated cluster mailboxes and commercial mailbox systems - all USPS-approved and available at competitive prices. From single-unit replacements to large-scale community installations, we deliver fast, reliable service and expert guidance every step of the way.

US Post Company is your trusted source for USPS-approved commercial mailboxes, replacement parts, and expert advice. We’ll help you fix delivery issues for good - while enhancing your property’s look and reliability. We'll also assist with any questions about your existing mailbox installation.