SHANGHAI’S environment watchdog has publicized new water conservation areas for the city’s four major tap water sources to ensure water safety.

Most of the water that residents drink comes from the upstream Huangpu River and three reservoirs — Qingcaosha, Chenhang and Dongfengxisha — at the mouth of the Yangtze River. The conservation areas are set up around these key sites, Shanghai Environmental Protection Bureau officials said.

Previously, Huangpu River served as the main tap water source for residents and so is deemed the Mother River of Shanghai. When the reservoirs were built and began operating in the last decade, it became essential to adjust the water conservation areas, the bureau said.

About 70 percent of residents are now drinking water from the mouth of Yangtze, while Huangpu mainly serves as a water reserve source for the city, Shanghai Water Authority said.

The conservation areas are principally categorized into two levels according to China’s water pollution prevention and treatment law. For the “top level conservation,” no construction project other than those to protect the water sources can be built or expanded within the designated area. All sewage discharge treatment must be demolished. Furthermore, no harbors, boat operations, oil tanks or farmland are allowed to be set up and no poultry can be raised.

Top-level conservation areas have been set up near the two water intakes for Jinze Reservoir in Qingpu District that began operating in late 2016. More than 6.7 million residents in Qingpu, Songjiang, Jinshan, Minhang and Fengxian districts, are getting water from the reservoir on Taipu River, the cleanest upstream branch of Huangpu River.

The top-level water conservation areas also include a 200-meter-wide area around Qingcaosha Reservoir on Chongming District’s Changxing Island. This reservoir supplies tap water to all downtown residents. A 50-meter-wide land area around the dam for the reservoir is also included.

Not far away from Qingcaosha, a section by the Yangtze River — 1 kilometer from the Chenhang and neighboring Baosteel reservoirs in Baoshan District — has also been marked as a top level conservation area, along with a site near the intake for Dongfengxisha on Chongming Island.

Secondary conservations have been set up in wider areas outside the top-level protective zones. In these areas, no building that will discharge waste water is allowed to be built. Existing plants and other projects within the secondary conservations will be required to reduce their waste discharge amounts.

A third-level protective zone and buffer areas are also set up where no waste water is allowed to be discharged into waterways to further protect the water source, the environmental protection bureau said.

Qingcaosha Reservoir, for instance, has a 5-kilometer buffer area around its intake that is monitored around the clock to ensure the reservoir can be shut if need be, the water authority said. Its water storage is adequate to sustain the city’s consumption for up to 68 days.

The buffer areas are especially essential for reservoirs by the Yangtze, because salt water pours into the river mouth every year from October to April, threatening the quality in the city’s waterways and reservoirs.