The Environmental Protection Agency knew enough about the lead water crisis in Flint, Mich., to issue an emergency declaration six months earlier than it did, according to the EPA's inspector general.

The IG's report, issued after months of investigation, said the EPA knew in June 2015 that state regulators were not doing enough to protect Flint residents by not including corrosion control chemicals in the water supply. But the emergency wasn't declared until January 2016.

Not including those chemicals in the water from the Flint River caused the acidic river water to corrode lead pipes. The lead went into the town's drinking water and sickened many residents.

"Region 5 had information that systems designed to protect Flint drinking water from lead contamination were not in place, residents had reported multiple abnormalities in the water, and test results from some homes showed lead levels above the federal action level," the report stated.

However, "EPA Region 5 did not issue an emergency order because the region concluded the state's actions were a jurisdictional bar preventing the EPA from issuing a(n) … emergency order."

Flint's residents are currently unable to drink their tap water without a filter. In April 2014, the city government, which then was controlled by the state, switched water sources from Lake Huron to the Flint River in an effort to save money.

Once the problem was discovered, the state was placed under federal and state states of emergency. The federal state of emergency lifted in August, though some federal agencies remain in the city.

Recent test results show homes still have high amounts of lead in their drinking water and only a few in the city have had their lead pipes removed.

According to the report, it took almost three months for local EPA officials to brief the national office on the issues regarding Flint's water. The EPA's Office of Enforcement and Compliance Assurance was first informed on the happenings in Flint by Region 5 employees.

According to emails released by the state of Michigan, EPA researcher Miguel Del Toral was investigating high lead levels in Flint homes in February 2015.

However, the EPA deferred to Michigan water regulators, many of whom were later charged with crimes related to the crisis. During the fall of 2015, the EPA let Michigan regulators begin responding to the crisis and didn't get more involved until Jan. 21, 2016, when EPA Administrator Gina McCarthy directed the agency to issue an emergency.

"The emergency order stated the EPA had determined that Flint's and Michigan's responses to the drinking water crisis were inadequate, and the EPA ordered specific actions to address a public health threat," the report stated.

Susan Hedman, the top EPA official in Region 5, would later resign for her role in the crisis.

The report stated the EPA had received "many" complaints about the drinking water in Flint between April 2014 and June 2015. By that point, the EPA also knew state and local authorities were not acting quickly to take any action to protect Flint residents from lead contaminated water.

"However, instead of acting immediately to protect human health, the state delayed action by awaiting the results of the second round of lead sampling (not anticipated until August 2015)," the report stated. "The state argued Flint had as many as 5 years from the date of the source switch to optimize corrosion control. The city of Flint also did not take action."

The report did note that it's rare for the EPA to declare an emergency in a city with its own water authority. However, there were enough clear signs from the situation on the ground that it should have acted with more urgency.

"While events were complicated, given what we know about the consequences of the Flint drinking water contamination, it is clear that EPA intervention was delayed," the report stated. "These situations should generate a greater sense of urgency. The EPA must be better prepared and able to timely intercede in public health emergencies like that which occurred in Flint."

The EPA said it's already taking into account the changes called for by the Inspector General and plans to continue to change its tactics.

"EPA fully understands the importance of providing additional training to appropriate management and staff on drinking water enforcement authorities, which is why we have already completed much of the training described in the Inspector General's report," the agency said in a statement. "We are also committed to updating the Agency's guidance for Safe Drinking Water Act emergency authority, as outlined by the OIG.EPA issued an order to the City of Flint and the State of Michigan as soon as it became apparent that the city and state were failing to address the serious problems with the Flint drinking water system. We will continue to review the OIG's findings."