Spare keys and key copies: who has a key to your home?
Updated · KeystoneProGuide editorial team
Why does it matter who holds a key?
Because keys are sometimes how burglars get in. In federal survey data for 2003 to 2007, residents who were home during an unlawful-entry burglary said in nearly four percent of cases that the offender had a key and used it. Most burglaries do not involve a key, and the same survey found that damaging or removing a door was the most common way in for forcible burglaries, but a key is a way in that no stronger door will stop. ALOA, the locksmiths' trade association, makes the same point about house sales: it calls rekeying the only way to secure a home against former key holders.
Where should a spare key go?
With a person, not under a mat. The King County Sheriff's Office in Washington State says to give a neighbor a key so you do not have to hide one outside, and warns that experienced burglars know to look in planter boxes, under doormats and above door ledges. Lower Moreland Township police in Montgomery County say to never hide a key outside and to leave a spare with a trusted neighbor. Northampton Township police in Bucks County give the same advice.
Northampton police add a point about key rings: do not keep home and car keys together. They say an address can be found from a license plate and keys can be quickly duplicated, so a lost key ring can lead someone to your door.
What if you are away for a while?
A neighbor with your key can check the house, and some police departments will look at it too. Radnor Township police in Delaware County run a Vacant House Watch: register online or on 610-688-0503 and an officer checks the outside of the house daily while you are away. The Kennett Square Police Department in Chester County offers house checks for residents on vacation.
Why do some copies not work well?
Because they are copies of copies. ALOA says keys wear with age and that duplicating an old or worn key can carry the wear into the new one. It suggests copying from an original key where you have one, and says a locksmith may be able to cut a fresh original from the lock's code when you do not. Keep one good original aside for this purpose, rather than on your daily key ring.
When should you stop copying and rekey instead?
When you have lost count. If you cannot say how many keys exist and who has them, more copies only add to the uncertainty. ALOA's advice after a move is to rekey as soon as possible, because keys are rarely all handed over, and to include the garage and any outbuildings. The same logic applies after lost keys or a household change. Rekey or replace explains the options and prices, and changing locks after you move covers the most common case.
Can you limit who copies your keys?
ALOA lists the need to minimize key duplication as one of the factors in choosing a lock, alongside the door's construction and the level of security you want, and says its members can advise on key control. It also lists designing master key systems among locksmith services. No public source read for this guide describes how restricted or "do not duplicate" keys work or how well they are enforced, so ask a locksmith to explain what any key-control product actually prevents.
How do master key systems affect renters?
They can decide whether you may change your own lock. ALOA says a landlord may require any new lock to fit an existing master key system, or may need a working key if a tenant changes the lock, so renters should check the rental office's policy first. That is ALOA's advice; no Pennsylvania rule on the point was found for this guide.
What about keypad and smart lock codes?
Treat each code or app account as a key. The Federal Trade Commission advises changing any default username and password on a connected device and not reusing passwords from other accounts. It also took action in 2020 against a maker of smart locks whose app had flaws that, the FTC alleged, prevented users from effectively revoking access. After you give someone a temporary code, remove it, then check that it no longer works.
What do key copies cost?
Not much for ordinary house keys. The national cost surveys give:
- Angi: $2 to $20 per key, depending on type.
- HomeAdvisor: $5 to $20 for standard house keys.
- Fixr: $10 to $25 for key duplication, and $75 to $100 for a house key replacement when a locksmith comes out, with the minimum trip charge applied.
Angi also lists rekeying multiple locks for a master key system at $30 to $90 per lock. Key copies are cheap enough that the real cost of poor key control is the rekey you need when copies go missing.
Where next?
Lock grades and ratings explains how to compare locks, and local businesses are on the locksmiths directory page.
Sources
- Doors and locks, King County Sheriff's Office
- Prevent Burglaries with these tips from Chief Smith!, Lower Moreland Township Police Department
- Crime Prevention, Northampton Township Police Department
- Victimization During Household Burglary (press release), Bureau of Justice Statistics
- Common Lock Issues: Advice and Info, ALOA Security Professionals Association
- Should I Change My Locks When I Move Into a House?, ALOA Security Professionals Association
- What Services Does A Locksmith Provide?, ALOA Security Professionals Association
- Canadian Maker of Smart Locks Settles FTC Allegations That it Deceived Consumers about its Security Practices, Federal Trade Commission
- Securing Your Internet-Connected Devices at Home, Federal Trade Commission
- How Much Does a Locksmith Cost? [2026 Data], Angi
- How Much Does a Locksmith Cost?, HomeAdvisor
- Locksmith Prices, Fixr
- Burglary Prevention Tips, Radnor Township Police Department
- Home Security, Kennett Square Police Department