Paldang Lake "Attention" Level Algae Alert Lifted... Hanam City Vows to Ensure Safe Tap Water Production

Hanam City in Gyeonggi Province (Mayor Lee Hyunjae) has been making every effort to ensure the production of clean and safe tap water through continuous monitoring and water quality management, even after the "Attention" level algae alert issued for Paldang Lake on August 14 was lifted on August 28.

Panoramic View of Hanam City Hall. Provided by Hanam City

An algae alert is a water pollution warning issued when the number of harmful cyanobacteria cells in rivers or lakes exceeds a certain threshold. This recent alert was triggered after pollutants flowed into Paldang Lake due to heavy rainfall in August, followed by a heat wave that raised water temperatures, resulting in harmful cyanobacteria exceeding 1,000 cells per milliliter in two consecutive measurements, which led to the issuance of the "Attention" level alert.

The algae alert system consists of three levels: "Attention," "Warning," and "Algal Bloom." The alert is issued by the Ministry of Environment when the number of harmful cyanobacteria cells measured weekly exceeds 1,000, 10,000, or 1 million cells per milliliter in two consecutive measurements, respectively.

In response to the algae alert issued in August, the city increased the use of coagulants and chlorine, and conducted weekly water quality tests for algal toxins and taste- and odor-causing substances to ensure that the tap water met quality standards. In addition, the city has maintained a constant monitoring system to enable immediate additional measures, such as the introduction of activated carbon, as needed.

Mayor Lee Hyunjae stated, "Although the algae alert has been lifted, harmful cyanobacteria may continue to proliferate due to the ongoing heat wave and high water temperatures," adding, "We will remain vigilant by strengthening continuous monitoring and thoroughly responding through advanced water purification processes."

Meanwhile, Hanam City once again demonstrated its stable management performance and tap water management capabilities by receiving the highest "A" grade for the second consecutive time in the "2025 Local Public Enterprise Management Evaluation" conducted in August by the Ministry of the Interior and Safety, targeting 113 basic water supply agencies nationwide.