Ding Ning lodged a claim for damages in court against Jilin PetroChemical on Friday, his lawyer, Hu Fengbin, said in an interview.
The case highlights growing demands for environmental protection and transparency in China.
Ding is claiming damages of 15 yuan ($1.86) for purchases of bottled water, as well as demanding an apology in a newspaper after an explosion at Jilin's plant on 13 November poured an estimated 100 tonnes of benzene and other poisonous substances into the Songhua river.
Harbin, a city of nine million people, pumps its water from the river. The chemical slick arrived in Harbin on Thursday.
By Saturday morning, the level of benzene in the river at Harbin had fallen to 3.7 times officially accepted levels, compared to 30 times on Friday morning. The 80km slick was due to have passed the city by early Sunday.
"Whoever brought risk to everyone's life should take the blame. I hope to use the law to exercise citizen's rights - to send a warning to the perpetrators - so we can avoid a repeat of such problems," Ding told Xinhua news agency.
Ding operates a small restaurant in Harbin and said business was badly hit by the water scare. His legal challenge is
unusual in a country where citizens rarely sue, and, even more rarely, win cases against powerful state-backed entities.
Residents want those who risked
people's lives to be punished
Jilin PetroChemical is owned by PetroChina, the country's biggest oil corporation.
Ten days after the spill, the Harbin government turned off the city's water and residents belatedly learned that the spill threatened their health. But many Chinese believe the Jilin authorities had sought to cover up the pollution and Harbin also first explained the shutdown as routine maintenance.
City held hostage
Even as the immediate threat to Harbin recedes, the drama of a major city held hostage by toxic chemicals is likely to increase pressure on the Chinese government to rein in widespread pollution.
"I have always been worried about having such a big chemical plant upstream," said the lawyer Hu, who grew up in Harbin.
"The government wanted to hide this. They said there was no pollution, but it should have been clear there was a spill. People here always learn too little, too late."
Even as local officials scrambled to supply Harbin's residents with safe drinking water, China's Prime Minister Wen Jiabao promised to focus the government's energies on cleaning up the environment.
This week Wen chaired a government meeting that promised to "basically contain environmental degradation" by 2010 and to "significantly improve" the environment.
But while China's leaders say they understand the gravity of the country's environmental problems, they also often say the country must continue to grow rapidly to avoid mass unemployment and social instability, which is likely to further tax the country's resources.
"The government wanted to hide this. They said there was no pollution, but it should have been clear there was a spill. People here always learn too little, too late"
"As the economy and society develop, conflict over water supply and demand will become even more pressing," China's minister for water resources, Wang Shucheng, said in a speech in mid-November.
Chinese government officials have estimated that 70% of the nation's rivers and lakes are polluted, and 30% of the length of China's major rivers is unfit for any human contact.
By popular reputation, the Songhua river is one of China's cleanest rivers. But according to official water monitors, more than half its length was unfit for direct human contact in 2003.
Hu said that many other Harbin residents had also called his office to sign onto the suit.
"I don't know whether we'll win, or even get a hearing, but it's clear that relying on the government to deal with pollution isn't enough. People are outraged, but they have to learn to make use of their power," he said.