The Environmental Protection Agency has begun investigating whether state or local officials discriminated against Flint, Mich., residents in actions related to the city’s drinking water crisis.

The federal agency wants to know whether Michigan’s Department of Environmental Quality, Genesee County and the city of Flint discriminated or had a discriminatory impact based on race, color, national origin or disability in notifying residents of the contamination in their tap water. Investigators will review whether government officials failed to implement procedures to comply with non-discrimination requirements.

The city of 100,000 has been reeling from lead contamination in its water supply after a...