The inner wall of HDPE water supply pipes is smooth and does not change over time, with low frictional resistance, energy saving, and pressure loss about 30% less than that of steel pipes. Smaller diameters can be selected than those of steel pipes. It has excellent hygiene performance, no additives, and no possibility of polluting drinking water. According to ISO standards, polyethylene material is classified as grade 0. It is a mold-free material. Compared with some other commonly used plastic materials, polyethylene has much higher resistance to mold and does not accumulate scale even after long-term use. It has a long service life, with a normal service life of over 50 years.