South Korea’s Supreme Court has ruled that a breath alcohol test generally cannot be used as evidence when police fail to give the driver water to rinse the mouth before testing. The court overturned a lower court conviction and returned the case to the Daejeon District Court for further proceedings.
The defendant was found asleep in the driver’s seat of a vehicle with its engine running on a road in Sejong on December 9, 2023. After being arrested and taken to a police station, the defendant underwent a breath test without first receiving water. The defense argued that residual alcohol in the mouth could have raised the reading.
- Incident date
- December 9, 2023
- Location
- Sejong, South Korea
- Required water
- Approximately 200 milliliters
- Court action
- Conviction overturned and case remanded
A Road Traffic Act enforcement rule requires police to provide drinking water so a person can rinse away alcohol remaining in the mouth before a breath test. The requirement entered the enforcement rules in July 2023, while National Police Agency guidance specifies approximately 200 milliliters of water.
A procedural safeguard with legal force
The trial and appellate courts maintained the conviction. They found that violating an internal enforcement guideline did not by itself make the test unlawful and cited the time that had passed since the defendant stopped drinking. The Supreme Court took a different view because the water requirement had become part of a legally binding enforcement rule before this test occurred.
The ruling does not immediately establish a final acquittal. It directs the lower court to reconsider the case without relying on the disputed breath-test result as proof of guilt. The remand proceedings will determine whether other admissible evidence can support the charge after that result is excluded.