Moving Into a New-Build Home? Rekey These Locks First
New-build homes have an under-discussed security gap: the lock on your front door was almost certainly installed months before you owned the house, and a working key existed the entire time construction was underway.
Who realistically has a copy
- The general contractor and every subcontractor who needed access during the build — electricians, plumbers, drywall crews, painters, inspectors.
- The builder's sales team and any real estate agents who showed the home before or during closing.
- Whoever managed the construction-site lockbox, if one was used — and lockbox codes get reused across a development far more often than buyers assume.
None of this implies bad intent from anyone involved — it's simply a lot of hands with a working key to a house that's about to be yours, and no practical way to verify every copy has been accounted for.
The other new-build-specific risk: an empty house is a visible target
A new-build development often has multiple unoccupied homes at once — staged models, unsold inventory, homes between closing and move-in. An unoccupied house with no one to notice a break-in, in a neighborhood where "unfamiliar car in the driveway" doesn't raise questions the way it would in an established block, is a real target profile. If there's a gap between closing and actually moving in, that gap is worth minimizing or at least worth having the locks changed before it starts.
What to actually do at move-in
- Rekey, don't necessarily replace. If the hardware itself is a reasonable grade, a locksmith rekey (new pins matching a new key) is faster and cheaper than full replacement — see when to call a locksmith vs. DIY.
- Check the grade while you're at it. Builder-grade hardware is very often Grade 3 — fine for interior doors, under-specified for an exterior door. This is a natural point to upgrade the front and back doors to Grade 2 or Grade 1; see the Lock Grade Guide.
- Do every exterior door, not just the front. Garage service doors and back doors were just as accessible to the construction crew as the front entrance.
- If the home came with a smart lock pre-installed, factory-reset it and set new PINs/accounts rather than trusting the builder's setup — see mechanical vs. smart deadbolts for what to check.
- Change or remove any construction lockbox still attached to the property after closing.
Rekey vs. full replacement: what actually makes sense for a new build
| When it's the right call for a new build | |
|---|---|
| Rekey | Hardware is a reasonable grade (Grade 2 or better) and functioning smoothly — just needs a new key nobody else holds |
| Full replacement | Hardware is Grade 3 or unrated on an exterior door, visibly worn, or you want to upgrade to a smart lock anyway |
Rekeying is a pin-tumbler cylinder swap — a locksmith replaces the internal pin stack to match a new key without touching the exterior hardware, typically 10–15 minutes per lock and meaningfully cheaper than full replacement when the hardware itself doesn't need upgrading.
The full move-in security checklist
- Rekey or replace every exterior door lock, including the garage service door.
- Confirm the grade on each exterior lock and upgrade where it's Grade 3.
- Factory-reset any pre-installed smart lock and create fresh accounts/PINs.
- Remove any construction lockbox from the property.
- Test the garage door opener's remote codes — some builder-installed openers ship with a default code that should be reset the same way a keypad code would be.
- Check that window locks throughout the house actually engage — a common punch-list item that gets missed on final walkthroughs.
- Confirm smoke/CO detectors are live and dated (unrelated to lock security, but a genuinely common new-build oversight worth checking at the same time).
Why this matters more for a new build than an existing resale
A resale home typically has one prior owner whose key history you can reasonably ask about and who has an incentive to disclose it honestly during a sale. A new build has an entire construction supply chain's worth of temporary access with no single point of accountability for tracking every copy — more hands, less visibility, and the process is often treated as routine by everyone involved except the eventual homeowner, who's usually unaware it happened at all.
What to ask the builder before closing
- Was the same key or lockbox code used across multiple homes in the development? Shared codes across a subdivision are common during construction for crew convenience, and worth confirming has been retired before you take possession.
- Is there a documented list of who held keys or codes during the build? Most builders won't have a perfect record, but asking signals it's a real concern and sometimes surfaces useful information about subcontractor access you'd otherwise not know about.
- Will the builder cover or discount a move-in rekey as part of closing? Some builders include this, or will coordinate it, if asked directly rather than assumed.
Smart-lock-equipped new builds: an added wrinkle
Some new-construction homes now ship with a smart lock pre-installed rather than a traditional deadbolt, often set up under a builder or vendor account during construction. Treat this exactly like a physical key: factory-reset it, remove any accounts that aren't yours, and set fresh credentials before move-in — a smart lock still tied to a construction-era account is functionally the same unresolved-access problem as an unrekeyed mechanical lock, just with more possible ways for someone to retain access (an app login, not only a physical key). See mechanical vs. smart deadbolts for the full account-security checklist that applies here.
FAQ
Is rekeying a new-build home really necessary if nothing seems wrong?
The whole point is that you can't verify "nothing's wrong" from a working-key standpoint — the risk isn't a specific known threat, it's an unverifiable number of people who had legitimate temporary access. The cost of rekeying is low relative to the uncertainty it resolves.
Does the builder usually rekey before handover?
Practices vary significantly by builder and aren't something to assume without asking directly — treat rekeying as your responsibility at move-in regardless of what the builder may or may not have done.
What if I'm moving into a resale home instead of new construction?
The same logic applies with a smaller scope — a prior owner, their family, a property manager, or past contractors may hold keys, and a move-in rekey is standard good practice for any home change of ownership, new-build or not.
Should I rekey immediately at closing or wait until move-in day?
As close to closing as possible, especially if there's any gap before you actually occupy the home — an unoccupied, newly-yours house with old keys still in circulation is exactly the window of risk this whole issue is about.
Does this apply to a newly-purchased condo or apartment unit the same way?
Yes, in principle — a condo or apartment unit had its own construction and pre-sale access history, though building-wide master key systems (see master key systems explained) sometimes mean a unit rekey needs coordination with building management rather than being purely a private decision.
The cost of a whole-house rekey is small relative to everything else spent closing on a new home, and it's the one item on the move-in checklist that closes a security gap nobody else is going to flag for you.