'overdrainage' originates from Modern English, specifically the prefix 'over-' (from Old English 'ofer') meaning 'excessive' or 'above', combined with 'drainage' (from the verb 'drain' + suffix '-age') meaning 'the act or process of draining'.

'drain' and 'drainage' entered English via Old French (e.g. Middle English 'drainen'/'drainage') and were later combined with the productive English prefix 'over-' to form the compound 'overdrainage' in technical usage (hydrology, engineering, medicine).

Initially, 'drainage' meant 'the act of removing water'; adding 'over-' shifted the sense to 'removal of water to an excessive degree', which is the current specific meaning of 'overdrainage'.