Glossary

Gradual damage

Harm that builds up over weeks, months or years, such as a slow leak, rot or corrosion, which most homeowners policies exclude.

Also called: continuous seepage, repeated seepage or leakage, long-term damage

Gradual damage is harm that accumulates instead of arriving in one event: a pinhole leak behind a wall, a dripping drain trap, a failed window seal, rust eating through a pipe. Homeowners policies cover abrupt, accidental losses, and the ISO form excludes wear and tear, rust, rot and deterioration, along with constant or repeated seepage or leakage over a period of weeks, months or years.

Insurers separate gradual loss from sudden and accidental loss by the evidence. Staining, rot, mineral deposits, corroded fittings and mold all suggest a long-running problem. Say a sink supply line seeps for a year and ruins the cabinet and floor beneath it (hypothetical). The insurer is likely to deny that damage as gradual. If the same line had burst in a day, the water damage would normally be covered, though any mold exclusion limit would still apply to the mold.

Hidden leaks are the hard cases. Some forms preserve coverage when the leak was concealed in a wall or under a floor and unknown to you. Protect yourself by checking under sinks and around water heaters and appliances, fixing small leaks promptly and keeping dated maintenance records. Once you find a leak, stop it, because damage that continues after you knew can be denied as neglect. The guide sudden vs gradual water damage explains the dividing line.

Last reviewed October 10, 2026

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Related terms

Sudden and accidental Wording insurers use to separate covered, abrupt losses such as a burst pipe from slow, foreseeable damage like a leak that has dripped for months. Wear and tear The slow breakdown of materials from age, weather and ordinary use, which homeowners policies exclude because insurance pays for sudden loss, not upkeep. Mold exclusion Policy wording that removes or caps coverage for mold, fungus and wet rot, usually leaving a small limit for growth that follows a covered water loss. Neglect Failure to use all reasonable means to save and protect property at and after the time of a loss, which the policy excludes to the extent the damage grows. Exclusion A policy provision that removes coverage for a stated cause, type of loss, property or circumstance that the coverage would otherwise reach.

Related guides

Washing machine, water heater and dishwasher leaks A sudden appliance leak is usually covered for the water damage and tear-out, but not for the failed appliance. Where slow leaks, drains and wear change that. Claims for hidden damage discovered later Can you claim damage found months after a storm, leak or fire? What decides it: cause, timing, late-notice rules, deadlines that run from the loss, and proof. Collapse coverage: what counts as a collapse The standard HO-3 pays only for abrupt collapse from listed causes such as hidden decay or a covered peril. Sagging, cracking and settling do not count. Home maintenance that keeps you insurable Which maintenance items insurers check, how neglect and wear and tear exclusions play out in a claim, and a yearly schedule that protects the house and policy. Polybutylene, galvanized and other pipes insurers dislike Which pipes make insurers decline, restrict or ask for a repipe, what a leak from them is covered for, and how to document a fix or shop for coverage. Slab leaks and tear-out coverage A sudden slab leak is usually covered for the water damage and the cost of breaking in, not the pipe. How the HO-3 splits it and where company forms cut it off.