Rekeying After You Move Into a Milwaukee Duplex or Flat
Updated 2026-10 · Milwaukee, WI
Why Milwaukee is different
By 1930 Milwaukee had about one duplex for every single-family house, and the city is known for the Polish flat, a cottage raised up to put a second unit in a half basement below. Most of those buildings are still standing in Riverwest, Bay View, the near South Side and the old North Side. Every one has had decades of owners and tenants, and none of them handed in every key.
Count the doors first
- Front door, and whether it is shared between units.
- Each unit door off a shared hall or stair.
- Side door to the back stair.
- Basement and any door to a shared laundry.
- Garage door and any service door.
- Storm doors with their own locks.
Write the list and decide which locks both households need a key to and which belong to one unit only. That is the conversation to have with the locksmith, and it is quicker before they arrive.
Rekey, do not replace, unless the lock is failing
If the locks work, rekeying makes every old key useless and keeps your hardware. Several locks set to one key in one visit is the efficient version. Old mortise locks on pre-war doors can be rekeyed too. Replace only the locks that stick, wobble or will not latch.
If you rent
Read the lease before changing anything. Most Wisconsin leases require the landlord's permission to change locks, and the landlord will want a key. The exception is Wis. Stat. 704.16, under which a tenant who gives the landlord a certified copy of a qualifying court order or criminal complaint can require the locks to be changed within 48 hours, at the tenant's cost. Legal aid services can explain how it applies to you.
If you own and rent out the other unit
Rekey between tenants as routine. A master key system lets you open every unit door you manage with one key while each tenant's key opens only their own. Keep a record of which key goes to which lock; it saves a lockout bill later.
Just moved in? Count the outside and shared doors and call for a price to rekey them in one visit.
Where to go next
Common questions
How soon after moving should I rekey?
As soon as you can arrange it, ideally the first week. You have no idea how many copies of the old keys exist.
Can I rekey a shared front door myself?
Not without agreement from everyone who uses it, and in a rental, the landlord. Locking a neighbour out of a shared entrance creates a bigger problem than the one you were solving.
Do old Milwaukee mortise locks take modern keys?
Many can be rekeyed or fitted with a new cylinder that takes a modern key, which keeps the original lock body in the door.