In addition to water intake, it can also prevent soil or rock particles around the well wall from flowing into the well and clogging the well pipe. It also supports and protects the well wall so that the pumping hole can be used normally. Some hard fissures and karst aquifers have stable well walls and no loose fillings. When pumping water, no filter pipes need to be installed. Loose pore-bearing layers or broken bedrock aquifers must all be installed with suitable filter pipes. Cement gravel filter pipes are also commonly used in agricultural water supply wells. The brick and wood well walls of civilian wells actually filter water and purify water resources.