In Missouri, the time for filing Driving While Intoxicated charges is limited by the general criminal statute of limitations. These time limits for bringing criminal charges are defined in RSMo. 556.036.
For a Misdemeanor including a first or second offense DWI the limitation is one year.
For a Felony including a third or subsequent DWI the limitation is three years.
Certain factors may extend the deadline for filing such as fleeing the jurisdiction, concealing onseself from prosecution or during a time when the accused is mentally unfit to proceed pursuant to 552.020.
The statute is satisfied as soon as criminal charges are filed either by a misdemeanor information or felony complaint or indictment.

