Cal. Civ. Code § 410.530
Weather-tight Elements
Operative Text
(A) An exterior openable window shall be considered weathertight only when:
(1) All panes of glass are in place, unbroken and properly sealed;
(2) The window sash opens and closes fully without excessive effort; and
(3) One of the following conditions is met:
(a) The window sash is sufficiently well-fitted such that it minimizes the infiltration of
air or moisture and the space between the window sash and the prime window frame is
no larger than c inch at any point on the perimeter of the sash in the case of double hung
windows and 1/16 inch in the case of casement windows; or
(b) A storm window is affixed to the prime window frame in such a way as to minimize
the infiltration of air or moisture.
(B) A door leading from a residence or dwelling unit to the exterior shall be considered to be
weathertight only if:
(1) All panes of glass are in place, unbroken and properly sealed;
(2) The door opens and closes fully without excessive effort; and
(3) One of the following conditions is met:
(a) The door is sufficiently well-fitted so that it minimizes the infiltration of air or
moisture and the space between the door and the prime door frame is no larger than c
inch at any point on the sides of the door; or
(b) storm door is affixed to the prime door frame in such a way as to minimize the
infiltration of air or moisture.
(C) Building and structural elements shall be considered weather-tight when all cracks and
spaces not part of heating, ventilating, or air conditioning systems are sealed to prevent
infiltration of exterior air or moisture.Massachusetts regulation 105 CMR 410.530 defines what it means for exterior windows, doors, and structural elements to be considered "weathertight" under the state's minimum housing standards. For windows and exterior doors, weathertightness requires intact and sealed glass panes, the ability to open and close without excessive effort, and either a tight-fitting sash or door frame (within specified gap tolerances) or an affixed storm window or door. For the broader building envelope, all cracks and gaps unrelated to HVAC systems must be sealed against outside air and moisture infiltration.
Plain English — not legal advice.
Under 105 CMR 410.530, compliant operators generally ensure that all exterior openable windows have unbroken, properly sealed glass, operate smoothly, and meet the specified gap tolerances—no more than the prescribed fraction of an inch between sash and frame—or have storm windows properly affixed. Exterior doors leading from dwelling units are held to a parallel standard, requiring intact glass, full operability, and either a well-fitted frame or an attached storm door. Operators also routinely inspect the building envelope for cracks or gaps in structural elements and seal them to prevent air or moisture infiltration, keeping records of inspections and repairs as evidence of ongoing compliance.
General guidance for property managers — not legal advice for your specific situation. Consult an attorney for advice on your case.
Section 105 CMR 410.530 establishes minimum weathertightness standards that landlords must meet for windows, exterior doors, and the building structure—meaning tenants have a right to housing where these elements keep out outside air and moisture. If a window has broken glass, won't open or close properly, has excessive gaps, or if an exterior door or structural element fails the standards described in this provision, that condition may constitute a violation of the state sanitary code. Tenants who believe these standards are not being met can document the conditions, notify their landlord in writing, contact their local board of health to request an inspection, or reach out to a tenant-rights organization to learn about available options.
General guidance for tenants — not legal advice for your specific situation. Consult a tenant-rights organization or attorney for advice on your case.
Generated September 30, 2026 — auto-generated, not yet human-reviewed. See /transparency for methodology.
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