watertight

Watertight is a property of a barrier or enclosure that prevents water from entering or leaking through under defined conditions. It is inherently relative: a seal that blocks dripping water may not withstand full immersion, and the exact standard (such as pressure, duration, or water type) should be specified when asserting watertightness.

In maritime and submarine contexts, watertight integrity prevents flooding after hull breaches. Ships use watertight compartments and doors to confine water, while submarines rely on bulkheads and seals to maintain buoyancy and safety under pressure. In packaging and cases, watertight designs rely on gaskets, o rings, and seals to keep contents dry during transport or storage.

In electronics and enclosures, watertight means the enclosure can resist water ingress to a defined degree, often indicated by an IP rating such as IP67 or IP68. Construction methods include molded seals, compression fittings, welding, and proper adhesion. Testing typically involves hydrostatic pressure, immersion, or spray tests to verify performance against the specified standard.

For buildings and civil engineering, watertight barriers protect basements, tunnels, and other structures from groundwater and seepage, using membranes, sealants, and drainage systems. The term is commonly used in product marketing but should be interpreted in light of the stated test conditions and life-cycle considerations.

Historically, the term originated in naval architecture to describe hulls and bulkheads designed to limit water ingress and maintain buoyancy after damage. While a truly watertight system can substantially reduce leaks, real-world performance depends on the quality of construction, maintenance, and the standards applied.