Why is it free to get water from a post office in the heart?

It is a charitable act to get water free of charge at the post office. Mail Heart Post Station is a particularly intelligent self-service water extractor, which is a public service post launched by China Post Hengtai Pharmaceutical Co., Ltd. You can enjoy free drinking water and feel cool all your life by scanning through WeChat, and you will know that there is a "life-saving artifact" AED in the cabinet, as well as intelligent security and intelligent fire camera when taking water. Therefore, the postal center station takes water for free, because it is a charity.