How is a valve described if it is completely leak-tight?

A valve that is completely leak-tight is described as resilient. Resiliency in this context refers to the ability of the valve to maintain its sealing capability under pressure and operational stresses, ensuring that no fluid escapes from the system. This characteristic is essential for maintaining system integrity, preventing leaks, and ensuring that the water distribution system operates efficiently.

Valves exhibiting resilience typically have high-quality construction materials and design features, such as rubber or elastomeric seals, which expand and contract without compromising their ability to remain sealed. This quality is crucial for valves used in water distribution, where leaks can lead to significant water loss, decreased system efficiency, and even contamination.

The other terms—substantial, durable, and effective—relate to various aspects of valve performance but do not specifically address the essential characteristic of being leak-tight. Substantial might refer to size or physical presence, durable to the lifespan or wear resistance of materials, and effective to overall functionality, but none of these focus directly on the leak-tight nature of the valve like resilience does.