Putting a mailbox on your house is legal, but whether you can actually use one depends on the U.S. Postal Service, not on the hardware. If your address already gets door delivery, mounting a wall box or cutting a mail slot is straightforward as long as it meets USPS specs. If your carrier currently delivers to a curbside box, moving that delivery point to your house requires a formal change in your delivery mode, and USPS grants those changes sparingly.
The Postmaster Decides, Not You
This is the step homeowners miss. You can buy a wall-mounted mailbox and bolt it to your siding in an afternoon, but if USPS hasn’t approved door delivery for your address, the carrier won’t use it. The USPS Postal Operations Manual states that door delivery “may be provided only with prior approval from the District Manager, and only if the box or mail slot can be efficiently, safely, and conveniently served by the carrier.”1U.S. Postal Service. USPS Postal Operations Manual – Modes of Delivery, Mail Receptacles, and Keys The same manual adds that door delivery “will not be available for new delivery points, except in very unusual circumstances.”
Call your local post office before you buy anything. The postmaster can tell you the current delivery mode for your address, whether a change is possible, and what the approval path looks like in your area. Skipping this call is how people end up with a handsome new mailbox on the wall and a carrier who keeps using the curbside box at the street.
One quirk worth knowing if you’re buying a home: the existing delivery mode stays with the property. USPS policy says the mode of delivery “cannot be changed arbitrarily prior to the new resident moving in.”1U.S. Postal Service. USPS Postal Operations Manual – Modes of Delivery, Mail Receptacles, and Keys A home that comes with door delivery keeps door delivery. A home that comes with a curbside box keeps the curbside box.
When Approval Is Realistic
Two situations make house-mounted delivery achievable. The first is that your neighborhood already has door delivery as its standard mode, which is common in older urban areas and dense residential blocks. In that case, you’re not changing the delivery mode at all, you’re just installing or replacing the receptacle.
The second is a medical or hardship exception. If you or someone in your household can’t physically retrieve mail from a curbside or cluster box, USPS will consider door delivery on request. You submit PS Form 1528 along with a doctor’s statement confirming the person’s inability to collect mail from the current point, and both go to the postmaster serving your address.2USPS.com. If I Have Hardship or Medical Problems, How Do I Request Door Delivery Approval is temporary and must be renewed each year. The local post office makes the final call.
Outside these two paths, USPS is unlikely to convert an established curbside address to door delivery, so plan accordingly before you start drilling into your house.
What the Mailbox or Slot Has to Look Like
Once door delivery is on the table, the receptacle itself has to meet USPS requirements.
Door Mail Slots
The opening must be at least 1.5 inches wide and 7 inches long, with the bottom edge sitting at least 30 inches above the finished floor. A weather flap is required. A horizontal slot’s flap hinges at the top; a vertical slot’s flap hinges on the side opposite the door’s own hinges.3USPS. Requirements for City Delivery Mail Receptacles An improperly installed slot can lead to damaged mail or a carrier refusing to use it.
Wall-Mounted Boxes
Wall-mounted residential boxes don’t have to come from an approved manufacturer list the way curbside boxes do. The Postmaster General doesn’t regulate their exact dimensions. What matters is that the carrier can reach the box easily. USPS doesn’t publish a mandatory height for wall-mounted boxes, but the 41-to-45-inch range required for curbside boxes is a practical target and keeps the box at a comfortable working height.3USPS. Requirements for City Delivery Mail Receptacles
House Numbers
Your house number must be visible from wherever the carrier approaches, at least 1 inch tall, and in a color that contrasts with the background.3USPS. Requirements for City Delivery Mail Receptacles Local building codes often require larger numbers, sometimes 4 inches or more, so check your municipality’s rule as well.
The Path to Your Door Becomes Your Responsibility
House-mounted delivery means a carrier walks onto your property every day, and USPS shifts some duties onto you as a result. Customers must keep the approach to the mailbox clear. If a carrier can’t safely reach the box, the postmaster can suspend delivery.3USPS. Requirements for City Delivery Mail Receptacles Shovel snow and ice from walkways and steps. Trim shrubs along the path. Keep the porch reasonably lit and uncluttered.
Dogs are the other common trigger for suspended service. A carrier who feels threatened by an unrestrained dog can stop delivery to your address, and sometimes to the whole block. Service resumes only after USPS is satisfied the animal will be confined during delivery hours. Until then, you pick up your mail at the post office.
Locking Boxes and What Can Legally Go Inside
A locking wall-mounted mailbox is allowed, but carriers are prohibited from accepting keys to private mail receptacles.4U.S. Postal Service. USPS Handbook PO-632 – Mailbox Locks and Keys Your locking box needs an incoming slot or compartment sized to accept mail without unlocking anything. You use the key on the retrieval side.
Once the box is mounted, federal law limits what can go in it. Under 18 U.S.C. ยง 1725, depositing unstamped material such as flyers, circulars, or advertising in a mailbox can bring a fine.5Office of the Law Revision Counsel. 18 U.S. Code 1725 – Postage Unpaid on Deposited Mail Matter The receptacle is reserved for material moving through the Postal Service. Enforcement against casual one-off notes is rare, but businesses that systematically stuff mailboxes have been fined.
Approvals That Aren’t the Post Office
Local Permits and Codes
Many municipalities regulate exterior modifications, and a wall-mounted mailbox or door slot can fall under those rules. Some jurisdictions require a permit for any exterior change; others exempt mailbox installations that meet USPS guidelines. Historic districts often add aesthetic standards covering style, material, and color. Call your local planning or building department before you drill. If your installation lands in a public right-of-way without approval, the local government can order it removed at your expense.
HOA Rules
If your home sits in an HOA community, the association’s Covenants, Conditions, and Restrictions likely govern what you can attach to the exterior. HOAs can dictate the mailbox’s design, material, color, and placement, and some require a uniform style across all homes. Review your CC&Rs and any architectural review guidelines before buying hardware. Violations can bring fines, forced removal at your cost, or a lawsuit from the association.6Nolo. HOA CC&Rs Explained: Rules, Rights, and Penalties An HOA can enforce its rules even when your box fully complies with USPS and local codes.
Landlord Permission
If you rent, a wall-mounted box or door slot is a modification to someone else’s property. You need the landlord’s written permission before installing anything, even if you plan to pay for it and restore the original condition on move-out. Most leases prohibit unapproved alterations. Tenants with a disability have the right to request reasonable accommodations for mail delivery, but coordinating with both the landlord and the local post office is still part of the process.