The protests came a day after almost 2,000 people gathered in central Baghdad to chants of "thieves, thieves, thieves", accusing the government of corruption and incompetence.
In the southern oil hub of Basra, around 500 people, waving banners and Iraqi flags, protested in front of the governor's office to demand a solution to the long-running problem of salty tap water.
"We demand the dismissal of the governor and of the provincial council; the time has come for Basra's people to get their rights," said Ziyad Tareq, a 24-year-old student.
"The local government is always promising improved water and electricity but they are liars and no longer have any credibility," Tareq said.
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"The temperature is 54 degrees (Celsius - or 129 Fahrenheit) in central Basra right now... The Basra people are very angry at their rulers."
Raad Jassim, an employee at the South Oil Co, said Basra residents were increasingly frustrated at their region's inability to capitalise on its massive oil wealth.
"Basra is feeding Iraq; it is bankrolling the country, and we do not even have water that is suitable for livestock," the 36-year-old said.
Yet it remains under-developed and has suffered from chronic power outages, poor water quality, uncollected waste and other problems that have led a growing number of Basrawis to call for autonomy.
Security forces were out in force today around the governorate, less than two weeks after violence erupted during a previous protest against electricity shortages.
"There is security here as if we were staging a coup against the government. We are demonstrating peacefully and all we want is our right to drink clean water," said Mahmud Shaker, a 52-year-old high-school teacher.
The protesters marched from the neighbourhood housing the Imam Hussein shrine, one of the holiest sites in Shiite Islam, to the governor's office.
"You are stealing from us in the name of religion," chanted a crowd that included many students, artists and journalists.