# Water Quality Monitoring: A Water Quality Dataset from an On-Site Study in Macao
## 1 Introduction  
Located in the south of China, in the Pearl River Delta, Macao is an international free port, one of the world's tourism and leisure centers, and one of the most densely populated regions in the world [1]. As there are no local rivers in Macao, rainwater harvesting and storage facilities are very limited, and there are no conditions for the construction of large-scale water storage projects. The source of drinking water has long been affected by salty tides, and local water resources have always been very scarce. Especially since 2005, with the intensification of the impact of salty tides, the security of Macao's water supply has been seriously affected. At present, about 96% of Macao's daily raw water is supplied by Zhuhai (Zhuhai is a city in the Guangdong Province of China, neighboring Macao, and is Macao's main source of raw water supply). The local reservoirs, which mainly play the roles of backup and emergency, have a total effective storage capacity of 1.9 million cubic meters, which is equivalent to the current status quo's water demand for seven days [1]. The Macao Special Administrative Region (SAR) government has always attached great importance to water conservation and has always taken water conservation as a prerequisite for the development, utilization, and protection of water resources. Macao has put in place a number ofmeasures to reduce water consumption and expenditure, and has been committed to implementing various water conservation measures over the years, which have greatly improved the efficiency of water resource utilization. The quality standards of the drinking water in Macao are implemented in accordance with the \"Standards and Rules for the Quality of Water for Human Consumption\" of the Macao Water Supply and Drainage Regulations. In order to enhance the safety and security of water quality, the government has revised the \"Regulations on Water Supply and Drainage in Macao\", which mainly includes increasing the number of monitoring items, revising the values of some microbiological, physical, and chemical water quality index parameters and analytical methods, and updating the minimum sampling frequency and the number of samples [2]. In order to raise the awareness of owners and property management companies regarding the maintenance and management of building water systems, the Macao Marine and Water Bureau (MWB) launched the \"Building Water Safety Program\" in 2018, with more than 50 of all the high-rise buildings in Macao participating in the program, successfully encouraging the owners and property management companies of more than 820 high-rise buildings to properly manage their buildings in accordance with the \"Guidelines on Maintenance of Building Water Systems\". The owners and property management companies of over 820 high-rise buildings have been encouraged to properly manage the internal water supply facilities of their buildings in accordance with the \"Guidelines on Maintenance of Tap Water System in Buildings\", and to carry out regular inspections, maintenance, and cleaning, including washing of water tanks and maintenance of water supply facilities at least once every six months, to ensure the hygiene and safety of the drinking water supply in their buildings and the stability of the water supply so as to ensure that members of the public can enjoy quality water. Tap water supply in buildings refers to the direct or indirect supply of urban public water to users. Direct water supply means that the water supply pipes inside a building utilize the excess water pressure of the public water supply network to deliver tap water directly to consumers, which is applicable to low-rise buildings. Indirect water supply means that the tap water is stored, pressurized, and then supplied to consumers, which is applicable to high-rise buildings. A building's water supply system mainly consists of underground and rooftop storage tanks, pipes, valves, pressurization equipment, and water appliances [3].