1. The level formed by the surface of still water; a levelling instrument in which water is employed.

Nuttall's Standard dictionary of the English language By Nuttall, P.Austin

• waterlevel,
• qater level,
• aater level,
• sater level,
• eater level,
• 3ater level,
• 2ater level,
• wzter level,
• wster level,
• wwter level,
• wqter level,
• warer level,
• wafer level,
• wager level,
• wayer level,
• wa6er level,
• wa5er level,
• watwr level,
• watsr level,
• watdr level

The adjective form of "water level" is "water-level".

The plural form of the word "water level" is "water levels"

The singular form of the word "water level" is "water level". The word remains the same whether it is singular or plural.