A water supply pipe entering a building should be:

A water supply pipe entering a building should be horizontal for several practical reasons. When a pipe is installed horizontally, it allows for the efficient flow of water into the building by utilizing gravitational forces correctly, ensuring that the water pressure is maintained over distance. This orientation also helps to prevent the accumulation of air pockets or sediments inside the pipe, which can occur in vertical or sloped installations.

Moreover, horizontal pipes are generally easier to install and maintain, as they can be run parallel to the ground structure of the building. This configuration also reduces the risk of pipe sagging or bending, which can lead to leaks over time. Proper drainage can be achieved more effectively with horizontal placement, allowing any potential moisture or condensation that forms to escape and not build up inside the pipe, which would not be effective in a vertical or improperly sloped pipe.

Understanding these principles is essential for ensuring that plumbing systems function correctly, maintain water quality, and are easy to service.