Flint, Michigan residents who pour themselves a tall, cool glass of tap water run the risk of permanently lowering their IQ due to the high lead content.
Flint’s tap water has contained double the amount of lead since the city switched its water source from Detroit to the Flint River to save money. The high lead content is caused by the more corrosive water coming into contact with service lines and city pipes, requiring stricter treatment than Flint is providing. 
On Thursday, the Genesee County health department declared a public health emergency in the cash-strapped city, recommending that people avoid drinking the water unless it has been filtered and tested to rule out the presence of excess lead. Governor Rick Snyder, however, has acknowledged that lead from aging water pipes is leeching into the city’s water, but refuses to declare the problem an emergency.
Flint residents had complained about their tap water for more than a year. The liquid coming from their faucets smelled bad, tasted bad, came out in a rainbow of sickening colors, and was making them sick. The government continually lied to them until the end of September, saying the contamination in the water had been taken care of and that the water contained “acceptable” amounts of lead. The metal is distributed to the brain, liver, kidney, and bones in humans, where it accumulates over time. Lead exposure is blamed for between 143,000 and 600,000 new cases of children developing intellectual disabilities each year. 
In tap water, the legal lead limit is 15 parts per billion (ppb), but no amount of lead is safe to drink.
As a result, an increasing number of children living in Flint are testing positive for elevated blood-lead levels. The percentage of Flint kids with elevated blood-lead levels has doubled in certain zip codes. Lead exposure in children can cause behavior and attention problems, hearing problems, kidney damage, decreased IQ and other serious health problems. Frighteningly, the damage is irreversible.
Snyder says his team’s data is incomplete, but he is dedicating $1 million to purchase lead filters for Flint residents and has ordered further testing and says he is improving corrosion control at the Flint water treatment plant.
Next year, Flint will once again be connected to Lake Huron water, just like Detroit. But changing the source of the city’s water might not matter much, if its treatment plant is incapable of properly treating the water.
 CBS News