Rekeying and replacing are two different jobs
A closing hands over a deed, a set of keys, and no way of knowing how many other keys exist. The sellers had some. So, at various points, may relatives, a contractor, a cleaner, a former tenant, or whoever borrowed a spare and never brought it back. None of that is recoverable afterward, which is why locks belong in the first week of owning a house.
In Waterbury the question is usually bigger than one front door. Census figures put the city's owner-occupied housing unit rate at 47.2 percent for 2020-2024, so under half the housing units here are lived in by their owners. Plenty of purchases in the Brass City are two- and three-family buildings, where a buyer inherits a common entry, a basement, a row of unit doors, and sometimes occupants already holding keys.
Rekeying leaves the hardware on the door and changes what is inside it - new pins, a new key, and every old key stops turning. Replacing means new hardware: a different deadbolt, a different lever, sometimes a different keyway. Connecticut's statute treats both as one trade, defining locksmithing to include the "inspection, installation, recombination, rekeying, service or repair of locks or locking devices" (Conn. Gen. Stat. s. 20-691).
Rekeying suits hardware that is sound, meaning it turns smoothly and the bolt throws all the way. Replacing earns its place when a lock is worn or damaged, or when its keyway cannot join the rest of the house on one key. Most houses need some of each, so house rekeying and new lock installation is usually one visit.
The count and the condition move the total, not the label on the job. Eight cylinders in four brands is a different afternoon from three in one. Travel, the hour, and whether a key is cut or simply matched sit in the same list of what moves the total on a whole-house rekey.
The doors nobody counts
Almost every new owner counts the front door and stops there. Walking the property with a notepad turns up more cylinders than expected, and the forgotten ones are the ones that stay on the old key for years.
On a two- or three-family the list forks. Exterior and common doors belong on the owner's key; individual unit doors are a separate question with rules attached, and locks at the change of a tenancy covers what the statutes say about the timing.
- The back or side door, often the one the household actually uses
- A basement or cellar entry, plus any bulkhead hasp or padlock
- The door between an attached garage and the house, exterior in everything but name
- A detached garage or shed whose key never came with the house
- Storm doors and mailbox locks, which nobody counts until a key is missing
One key for everything, or deliberately not
Locks keyed alike all open with a single key, leaving one key to keep track of. Locks keyed different each need their own, which is what you want when access to one unit should not travel with access to the rest.
Getting to one key is a hardware question, not a preference. Cylinders have to share a keyway, and brands are not freely mixable: as one hardware supplier puts it, "Not all brands are compatible for keying alike." A house that gained a different lock every decade or so can carry three or four keyways, which is where a rekey quietly becomes a replacement on some doors.
One key for everything is not always the goal. An owner living in one unit of a three-family has reason to keep a tenant's door off the key that opens their own. The workable middle is one key for the doors the household uses daily, and separate keys for anything shared or rented.
Grades, and what a grade describes
Deadbolts fall under ANSI/BHMA A156.5, the standard for auxiliary locks, which covers auxiliary bored and mortise locks, rim locks, cylinders and push button mechanisms. Grade 1 is the highest level of performance, followed by Grade 2 and Grade 3, and residential deadbolts sit mostly in the lower two.
A grade describes the lock, though, and not the door. On the older wooden doors common across established Waterbury neighborhoods, the first thing to give way is rarely the bolt. It is the jamb, the strike plate, or the short screws holding that strike into soft casing.
A Grade 1 deadbolt in a frame that splits keeps the bolt intact while the door opens anyway. A bolt that does not extend fully into its strike, a door that has dropped on its hinges, a strike fastened to trim rather than framing - those matter more than the number on the box.
Sequencing it around the closing
The smoothest version of this job is the one where the count is right before anyone starts. A walkthrough before closing is the moment to open every exterior door and note the brand stamped on the cylinder face. Photographs of each lock and each inherited key are more useful than they sound.
A key that opens nothing is information. It means a cylinder was changed somewhere and the key never collected, or that a door exists which has not been found yet. Better to learn that at the walkthrough than six months in.
Then the order runs from the outside in: exterior doors first, then common and basement doors in a multi-family, then outbuildings and mailboxes once the inherited keys have been tried. Hardware that will not lock at all jumps the queue, and a bolt that refuses to throw is urgent rather than scheduled. The plan starts from the door count and the keyways, which is where lock and key work across the Brass City starts.
Three short answers
Is rekeying enough after buying a house, or should the locks be replaced?
Rekeying is enough whenever the hardware itself is sound, because it retires every old key while leaving the lock on the door. Replacement is the answer for locks that are worn, damaged, or built on a keyway that cannot join the rest of the house on one key. Most houses turn out to need a mix of the two. The deciding factor is the condition of each cylinder, not the age of the house.
Can every door in the house be put on one key?
Often, but not always, because keying locks alike depends on the cylinders sharing a keyway and not all brands are compatible with one another. A house that gained a different lock every decade may carry several keyways on its exterior doors, and unifying them can mean swapping some cylinders rather than just rekeying them. A locksmith can usually tell which doors will join the set by reading the cylinder faces.
How many keys should a new owner expect to end up with?
Fewer than the pile handed over at closing, and more than one. A common outcome is a single key for the doors the household uses daily, with separate keys for anything shared, rented or lent out. On a two- or three-family that usually means one key for the common and exterior doors, and individual keys held per unit.