You can put extra locks on apartment doors in most cases, but you almost always need your landlord’s written permission first. The lease agreement controls what counts as an allowed modification, and local landlord-tenant law fills in anything the lease leaves out. The one clear exception is portable security devices that don’t alter the door or frame, which you can generally use without asking.
Start With Your Lease
Adding a lock counts as a modification whenever it involves drilling, screwing, or otherwise changing the door or frame. That puts it squarely under whatever alteration clause your lease contains. Three patterns are common:
- A flat prohibition on modifications. You would need a written exception before installing anything permanent.
- Prior written consent required. This is the most common setup and gives you a clear path.
- Silence on locks and modifications. State and local landlord-tenant law fills the gap, and asking permission first is still the safe move.
A handful of states give tenants a statutory right to request deadbolts regardless of what the lease says, and in those places the lease clause takes a back seat. Most states don’t go that far, so read your lease as the starting authority.
Locks You Can Add Without Permission
Portable security devices sit in a different category from installed hardware because they don’t permanently alter anything. Common options include:
- Door jammers and security bars that brace against the floor and wedge under the doorknob. Fully removable, no marks.
- Travel locks that slip into the strike plate and block the door from being opened from outside. Made for hotel rooms, but they work on apartment doors.
- Door reinforcement plates that attach with the existing strike plate screws, adding strength without new holes.
Since none of these modify the property, landlords generally have no basis to prohibit them. The catch is that they only work while you’re inside. A door jammer won’t secure the apartment when you leave for work. Treat these as supplements to the lock you already have.
Locks That Need Landlord Approval
Anything bolted, screwed, or drilled into the door or frame is a permanent modification. That covers deadbolts, chain locks, slide bolts, and surface-mounted rim locks. Even a simple chain lock requires screws into the door and frame, so it falls under the lease’s modification clause.
Deadbolts are the strongest upgrade, but installing one means boring a hole through the door and cutting a recess into the frame. Poor installations can crack the door, misalign the frame, or defeat the lock’s own security. Landlords have legitimate reasons to require a professional here, and many do. Professional deadbolt installation typically runs $70 to $200 for a standard job, with wide variation by area and lock type.
Frame-mounted security bars also count as permanent modifications, even when the marketing suggests otherwise. If it leaves screw holes when removed, it needs permission.
How to Ask, and What Your Landlord Will Likely Require
A written request is worth more than a hallway conversation. Send an email or letter that covers three things: the type of lock, why you want it, and who will do the installation. If you’re responding to a specific concern like a recent break-in nearby, say so. Landlords tend to be more receptive when the request is clearly about security.
Expect conditions attached to any approval. The most common are:
- Professional installation by a licensed locksmith.
- An approved lock brand, type, or grade.
- A copy of every new key for the landlord.
That last one is not really optional. Landlords need access for emergencies, inspections, and court-ordered entry. Adding a lock and refusing to hand over a key creates a separate lease violation, and some landlords treat that refusal as grounds to start eviction proceedings. Get the approval and every condition in writing. A verbal “sure, go ahead” gives you no protection if the landlord later claims the work was unauthorized and charges you for repairs.
Fire Code Limits That Apply No Matter What
Not every lock you might want is legal to install, and fire and building codes override landlord approval. The International Building Code requires egress doors to be “readily openable from the egress side without the use of a key or special knowledge or effort,” and it limits egress hardware to one motion to unlatch. Individual dwelling units get an exception allowing an additional releasing motion, which is why a deadbolt paired with a knob lock is acceptable on an apartment door.1ICC. IBC 2021 Chapter 10 Means of Egress
The lock type that causes real trouble is the double-cylinder deadbolt, which needs a key to open from both sides. In a fire, if you can’t find the key, you can’t get out. Most local fire codes either ban double-cylinder deadbolts in residential apartments or restrict them so heavily that they’re effectively off-limits. The NFPA Life Safety Code takes the same position by prohibiting locking devices that impede egress or that cannot be easily disengaged. Stick with a single-cylinder deadbolt: keyed outside, thumb-turn inside.
Stacking multiple locks is its own concern even when each one is code-compliant. Every added lock is another motion between you and the hallway during an emergency.
Stronger Rights in Two Situations
If you’re experiencing domestic violence, you likely have stronger rights than a typical tenant. A growing number of states, including California, Illinois, Maryland, and Oregon, have statutes letting survivors request a lock change from the landlord or, if the landlord doesn’t act quickly enough, change the locks themselves. The usual framework gives the landlord 24 to 48 hours to act after receiving a request with supporting documentation like a protective order or police report. Even under these statutes, tenants are typically required to provide the landlord a new key within a short window and to use locks of equal or better quality. The Violence Against Women Act adds housing protections for survivors in federally subsidized housing.2HUD. Violence Against Women Act (VAWA) Contact a local legal aid organization or domestic violence hotline before acting, so you know what your state allows.
Tenants with disabilities have separate rights under the Fair Housing Act, which requires landlords to allow reasonable modifications tied to a documented disability. If a standard lock is hard to operate because of arthritis, limited hand strength, or impaired dexterity, you can request a change such as a lever handle in place of a round knob, or a smart lock operated by keypad or phone. In most private housing you pay for the modification, but the landlord cannot refuse a reasonable request tied to a disability. Put the request in writing and keep the response.
What Happens If You Install a Lock Without Permission
Unauthorized installation feels minor until the landlord finds out. The consequences tend to stack:
- Lease violation. The landlord may issue a cure-or-quit notice giving you a set number of days to remove the lock and restore the door, or move toward eviction if you don’t comply.
- Repair charges. Damage to the door, frame, or existing hardware comes out of your security deposit at move-out, and anything over the deposit can be pursued as a balance owed.
- Forced removal. The landlord can require you to remove the lock and return the door to its original condition at your expense.
- Lockout costs. If the landlord doesn’t have a key and needs emergency access, you may owe the locksmith fee. Emergency lockouts commonly run $50 to $400 depending on time and complexity.
The total often exceeds what it would have cost to ask permission and do the installation properly.
If Your Landlord Says No
A refusal doesn’t leave you without options. Start by documenting why you feel unsafe. Police reports for break-ins in the building carry weight. A written complaint about a substandard existing lock creates a paper trail supporting a habitability claim.
Practical steps that don’t require permission include using a door jammer while you’re home, adding a peephole if your lease allows it (many landlords do, since the hole is small and easily patched), and installing a video doorbell that mounts with adhesive rather than screws. You can also contact your local housing authority or a tenant rights organization to check whether the building code in your jurisdiction requires lock standards your apartment doesn’t meet. If the unit is out of compliance, the landlord can be compelled to upgrade regardless of preference.
One boundary worth knowing before you spend money on extra hardware: your landlord already owes you a working lock on the exterior door. The implied warranty of habitability, recognized in nearly every state, covers this. If the existing lock is broken, loose, or unreliable, that’s a repair the landlord has to make. Adding a second lock is not a substitute for demanding the first one work.
If your safety concern is serious and immediate, such as stalking or a threat of violence, don’t wait for the landlord to come around. Contact local law enforcement, a domestic violence resource, or a legal aid office. An attorney can help you find the fastest legal path to securing your door.