Flushing Water Quality during the Period of October 2023 – September 2024
Leveraging seawater as a sustainable water source, since the late 1950s, Hong Kong has extensively abstracted seawater, which is treated to remove larger impurities and disinfected with sodium hypochlorite before being supplied to users for toilet flushing. In addition, starting from March 2024, the Water Supplies Department (“WSD”) is supplying recycled water for toilet flushing with a view to containing the fresh water demand. To ensure satisfactory quality of treated seawater (“salt water for flushing”) and recycled water for flushing on grounds of aesthetic acceptance and hygiene, the WSD has established the Water Quality Objectives (“WQO”) of Salt Water for Flushing Supply and Water Quality Standards for Recycled Water respectively. The public may visit the WSD website (https://www.wsd.gov.hk/en/core-businesses/water-resources/seawater-for-flushing/index.html) for information on flushing water.
Salt water samples for flushing supply were collected at salt water pumping stations, salt water service reservoirs, salt water tanks and customer ends, while recycled water samples for flushing supply were collected at recycled water treatment plant, recycled water service reservoir and customer ends. During this reporting period, the compliance rate for the overall quality of salt water and recycled water supplied for flushing purposes is 99.1%(Note 1), which fully meets the performance target of achieving a ≥97% compliance rate.
Notes:
The compliance rate of flushing water quality is calculated as follow:
