The spectrum of drowning types is as diverse as are human activities and locations, be it at home, work, play or other preoccupation. However to achieve uniformity in reporting from the myriad of agencies compiling drowning data, the definition of drowning, as it relates to unintentional injuries (i.e., not assaults, homicides or suicides), and the activities and locations where they occur must be limited. Consequently, unintentional injuries, fatal and non-fatal, for drowning are encoded using the WHO International Classification of Diseases (ICD) 10th Revision, 2010 (6):
• Watercraft-related drowning V90 (watercraft accident), V92 (no watercraft accident)
• Bath tub-related drowning W65 (not fall-related), W66 (fall-related)
• Swimming pool-related drowning W67 (not fall-related), W68 (fall-related)
• Natural water-related W69 (not fall-related), W70 (fall-related)
• Other specified water-related W73
• Unspecified water-related W74

Despite the introduction of new ICD-10 drowning codes and subcategories, Lu, et al, (2010) found that a significant majority of reporting countries were using the "unspecified" drowning code (ICD-10 W74) and few if any of the subcategories (16). The authors noted that the reports submitted by 1 in 7 countries were unacceptable. Only 14 of the 69 countries reporting unintentional injury by drowning fatalities were using the correct ICD-10 codes 90% of the time. Underreporting and misclassification of unintentional drowning are significant barriers to prevention.