Quick answer
A master key system is a keying plan where one master key opens every lock, sub-master keys open groups of doors, and individual change keys open single doors. It lets owners and managers carry one key while staff carry only what they need, and it means a lost key requires rekeying one door, not the building. Most systems can be built from existing commercial locks. Pair it with a restricted keyway so keys can't be copied without authorization. Small office systems in San Diego typically start around $300. See master key systems.
In this guide
The problem it solves
Without a system, every door has its own key and every person who needs access gets a copy. The owner carries a ring. The manager carries a ring. When someone leaves, nobody knows which keys they had, so either everything gets rekeyed at real cost or nothing does and the risk stays. Keys get copied at hardware stores. Within a few years the building's actual security is whatever the most careless former employee decided.
How the hierarchy works
Think in levels. The master key at the top opens every lock in the system. Below it, sub-master keys each open a defined group: one floor, one department, one building on a multi-building property. At the bottom, change keys open a single door or a small set. A restaurant might have a master for the owner, a sub-master for managers that opens the front, the office and the storeroom, and change keys for staff that open only the staff entrance. A medical office adds a sub-master for the practice manager that includes the records room and excludes the medication cabinet.
When a change key is lost, one door gets rekeyed. When a sub-master is lost, only that group. The master stays in the safe.
Restricted keyways: the half people skip
A master key system on a standard keyway can be copied at any hardware store, which quietly defeats the point. A restricted keyway uses blanks that aren't sold to the public, and the locksmith cuts copies only with written authorization from the person you designate. With it, the number of keys in existence is the number you authorized. Without it, you're guessing. For any business with staff turnover, restricted keys are what make the system a system.
Who it's for in San Diego
- Offices and coworking in Kearny Mesa, UTC and downtown with private suites, server rooms and supply closets.
- Medical and dental practices in Hillcrest with records rooms and medication storage.
- Restaurants and bars from the Gaslamp to Newport Avenue where owner, manager and opening crew need different access.
- Property managers and HOAs with mailrooms, pool gates, storage and utility rooms. See property manager services.
- Warehouses in Otay Mesa with offices, cages and yards on separate levels.
What it costs and how it's built
Most commercial cylinders can be re-pinned into a master system without new hardware, which keeps a small office system in the low hundreds of dollars, close to the cost of a plain rekey. Restricted keyways, interchangeable cores and new hardware add to it. The process is a site survey to count doors and talk through who needs what, a written key schedule, the installation, and the keys cut and labeled. Keep the schedule on file, because the next change is quick when it's documented. Details on our master key systems page and prices page.
Written by Mark Hanna, owner and lead locksmith of Action Locksmith San Diego (CA LCO License #7199). Published , last updated . Prices mentioned are typical San Diego ranges; see the prices page for details.
