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Mount Prospect, IL Building Safety: Door Locking Hardware (2026)

Some Restrictions
Compiled from the official code textEditor Martyn O'NeillLast verified September 2026

Key Facts

Apartment entrance doors
Must self-lock with a deadlocking latch when closed
Exemption
A 24 hour doorman
Window lock zone
Within 20 feet of ground or 10 feet of roof, stair or porch
Sash window opening
At least 4 inches and no more than 6 inches when locked
Unacceptable latches
Storm window and screen window latches
Code official
Director of community development

Summary

In the Village of Mount Prospect, apartment building entrance doors must lock automatically with a deadlocking latch when closed unless a 24 hour doorman is on duty. Every window and sliding door within twenty feet of the ground also needs a window lock under the Village Code's property maintenance amendments.

26. A new subsection 304.13.3, Window Locks, shall be inserted to be and read as follows: 304.13.3 Window Locks. Every window and sliding door within twenty feet (20') of the ground, or ten feet (10') of an adjacent roof, exterior stairway, fire escape, porch, or some other means of access, requires a window lock. ... ... 28. A new subsection 304.15.1, Door Security, shall be inserted to be and read as follows: 304.15.1 Door Security. Unless there is a 24 hour doorman, all apartment building entrance doors (front, rear, side, garage) must automatically lock with a deadlocking latch when closed. A key (or electric door buzzer) is required to open such doors from the outside, and a knob, handle or panic bar from the inside. In the case of the front door of a lobby, either the inner or outer foyer door must meet this requirement.

Full Breakdown

Door security in the Village of Mount Prospect comes from two amendments to the 2021 International Property Maintenance Code, both adopted in section 21.603 of the Village Code and applied to all buildings and real estate in the Village by section 21.602.

Subsection 304.15.1, Door Security, covers apartment buildings. Unless there is a 24 hour doorman, every entrance door, whether front, rear, side or garage, must automatically lock with a deadlocking latch when closed. Opening from the outside takes a key or an electric door buzzer, while opening from the inside takes a knob, handle or panic bar. For the front door of a lobby, either the inner or the outer foyer door must meet the requirement.

Subsection 304.13.3, Window Locks, reaches sliding doors as well as windows. Every window and sliding door within twenty feet (20') of the ground, or ten feet (10') of an adjacent roof, exterior stairway, fire escape, porch, or some other means of access, requires a window lock. A sash window that slides up and down must also carry a device that allows the window to be opened at least four inches (4") and no more than six inches (6") when the lock is activated. Storm window and screen window latches are not acceptable.

Related amendments keep the hardware working. Subsection 605.5 requires intercom systems, whether installed as part of the original construction or added later, to be maintained in good working condition and labeled with the unit number or occupant name, and the removal of such a device is prohibited and does not constitute repair or maintenance. The code official is the director of community development or a duly authorized representative, and an appeal from the official's interpretation goes to the village manager under subsection 107.

Violations & Fines

Section 21.403A fines each violation of chapter 21 in the amount set in appendix A, division III, and each day a violation continues is a separate offense. Section 21.403B lets the village go to court to restrain, correct or abate the violation. A building without self-locking entrance doors, or a ground-accessible window without a lock, is cited by the department of community development under subsections 304.15.1 and 304.13.3.

Frequently Asked Questions

Which doors must lock automatically in the Village of Mount Prospect?
Under subsection 304.15.1, all apartment building entrance doors (front, rear, side, garage) must automatically lock with a deadlocking latch when closed, unless there is a 24 hour doorman. In a lobby, either the inner or outer foyer door has to meet the requirement, and a key or electric door buzzer must open it from outside.
What window locks does the Village require?
Subsection 304.13.3 requires a lock on every window and sliding door within twenty feet (20') of the ground, or ten feet (10') of an adjacent roof, exterior stairway, fire escape, porch, or other means of access. Sash windows also need a device holding the opening between four inches (4") and six inches (6"). Storm window and screen latches are not acceptable.
Does the automatic door lock rule apply to single-family homes?
Subsection 304.15.1 is written for apartment building entrance doors, so its deadlocking latch and key or buzzer rules address apartment buildings. The window lock rule in subsection 304.13.3 is worded differently: it covers every window and sliding door within the stated distances and does not limit itself to apartments.
Who enforces the lock rules and how does an owner appeal?
The code official, meaning the director of community development or a duly authorized representative, enforces the property maintenance amendments. Any person can appeal the code official's interpretation of the code, or request a modification, to the village manager under subsection 107, and fines for chapter 21 violations are set in appendix A, division III.

Sources & Official References

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