Generally speaking, the inflow of water should be slow, not straight; The water flowing out should be curved and affectionate. If it is sewage, it should not stay for too long, but it is necessary to set up relevant columns at the exit, such as iron mesh, grit chamber and curved head. (Not to mention the role of geomantic omen, which has a positive effect on preventing mosquitoes, mice, cockroaches and other pests from entering the house and protecting the environment), and it is not advisable to go straight, otherwise it will be easy to commit mass annihilation or not gather wealth at home.
In ancient times, there was a saying that "the water in the south of the mountain is called Yang, and the water in the north of the mountain is called Yin". In the past, houses in rural areas were basically facing south, so they had yin and yang relative to water. The ditch in front of the house is generally in the south, and the water in the north is sunny, so it is called "Yang ditch". Speaking of the use of the gutter, these old people said that one of the most important uses is drainage.