Drain spouts have been pretty standard on camping coolers since their inception early in the 20th century. While cheap, super-market sourced 100% foam coolers do not feature drains, the majority of camping coolers do. They are most often located towards the bottom of the cooler where it is possible to drain melted ice water without tilting the cooler or dumping it upside down.
Many camping cooler drains are advertised as being ‘leak resistant’. This usually means a tightly fitting plug that goes into the drain bore and can be removed to allow immediate drainage. Over time, these plugs submit to the wear and tear of the active lifestyle and can lose their tight fit. Fortunately, replacement caps are not hard to come by and can often be sourced from the manufacturer. Igloo coolers even feature threaded drain spouts that actually fit a standard 2-liter bottle cap!