LANSING, Mich. — Two Michigan environmental regulators implicated in the Flint water scandal pleaded no contest to a misdemeanor Wednesday in exchange for more serious charges being dropped, bringing to six the number of officials who have agreed to such deals.

Stephen Busch pleaded no contest to disturbing a public meeting, and Michael Prysby pleaded no contest to a count of violating Michigan’s Safe Drinking Water Act. They had been charged with felonies, but those charges and others were dismissed under the terms of their deals that also require them to testify against others, if needed.

A no contest plea is not an admission of guilt but is treated as such for sentencing purposes. Their sentencings are scheduled for Jan. 23.

The plea from Busch, a water supervisor in the state Department of Environmental Quality, relates to his failing to address concerns during an unruly January 2015 meeting in which Flint residents complained about the city’s discolored and smelly water after the April 2014 switch from a Detroit-area system to using the Flint River.

Busch, who had faced involuntary manslaughter and other felony charges, said in a Flint courtroom Wednesday that he had conversations with state Health and Human Services Director Nick Lyon about legionella bacteria before March 2015 — many months before Lyon and Gov. Rick Snyder publicly announced a deadly Legionnaires’ disease outbreak in the Flint area. Some experts have blamed the outbreak on the use of the river.

Lyon, a member of Snyder’s cabinet, is the highest-ranking of the 15 state or local officials to be charged in relation to the water crisis.

The plea from Prysby, a DEQ water engineer, relates to the improper permitting of Flint’s water treatment plant during the switch.

Todd Flood, a special prosecutor hired by Michigan Attorney General Bill Schuette, put on the record parts of Prysby’s cooperation to date. They include statements that the river water was not tested before being distributed to residents, that an environmental order was improperly used to facilitate the financing of a planned move to a new regional water pipeline, and that two state-appointed emergency managers were ultimately the ones who decided to put the city’s water treatment plant back into full service before it was ready.

Both Prysby and Busch have been on paid leave. They were among the first officials to be charged in connection with the water crisis, along with a Flint water official who went on to take a deal. Prysby’s misdemeanor carries a maximum sentence of one year in prison. The punishment for Busch’s charge is up to 93 days in jail.

His lawyer, Mark Kriger, declined to comment late Wednesday.

The amended charges for both men will likely be dismissed in a year if they continue to cooperate and complete probation. None of the other officials to plead no contest — including Flint’s former utilities director, the state’s disease control director and another DEQ employee — have served time.

Flint ran into extraordinary trouble when the emergency managers appointed by Snyder put the city on water from the river while a pipeline was being built to Lake Huron. The corrosive water was not properly treated due to an incorrect reading of federal rules by state regulators, and lead leached from old pipes into homes and led to elevated levels of the toxin in children.