A bus driver for US rock group The Dave Matthews Band pleaded guilty on Wednesday to dumping 800lb (360kg) of human waste onto a sightseeing boat.
Bus driver Stefan Wohl was also fined $10,000 (£5,200)
Stefan Wohl got 18 months probation and 150 hours community service for reckless conduct and discharging contaminates into the Chicago River.
The sewage poured onto the open deck of a cruiser that was carrying more than 100 passengers last August.
The band have already donated $105,000 (£54,445) to environmental groups.
Mr Wohl, 42, from Selma, Texas, originally denied discharging waste from Chicago's Kinzie Street Bridge.
But a surveillance camera at a nearby health club proved the bus was on the bridge at the time.
The Dave Matthews Band contributed to environmental groups
The Dave Matthews Band, none of whose members were on board during the incident, co-operated in the investigation.
They offered their "deepest apologies" to the boat's passengers, who were on an architectural tour.
Mr Wohl was also fined $10,000 (£5,200), which will go to the Friends of the Chicago River conservation group.
A separate legal action filed by Illinois Attorney General Lisa Madigan, seeking $70,000 (£36,300) damages, is pending.