Snyder said he couldn't testify because he has to deliver a budget presentation to the state legislature that day, according to his spokesman, Dave Murray.
That presentation is expected to detail "significant resources directed to long-term plans to help the people of Flint," Murray told CNN.
The committee that wanted Snyder to testify wrote to him saying that Congress "has not heard testimony from you on the Flint water crisis."
"Unfortunately, a prior Congressional hearing this week did not include top state officials, including emergency financial managers appointed by you to run the city of Flint," the letter said.
"Seeing how it was your administration's decisions that led to this public health crisis, including Michigan's Emergency Manager Law, we believe it is important to hear testimony from you on this matter."
The Democrats-only committee does not have subpoena power.
Last week, Washington lawmakers
began trying to figure out why dangerously high levels of lead remained in Flint's water supply for months, who should be blamed for it and what action could be taken to help the city's residents.
The U.S. House of Representatives' Committee on Oversight and Government Reform focused on Flint's water crisis, which was characterized by several lawmakers as a failure of government on all levels: local, state and federal.
Individual lawsuit filed
Separately, the family of a 2-year-old girl from Flint, who tested high for lead levels, has filed a federal lawsuit against various officials in Michigan and Flint, including Snyder.
The lawsuit claims the toddler experienced "serious physical and emotion injury due to her exposure to the toxic water."
According to the family's attorneys, the suit is the first individual (non-class action) lawsuit brought against the city of Flint and Michigan state.