It depends on each country how they interpretate. For example im from chile, and i got very clear what “Water level” means in this case, because i readed the whole manual before start using it and its advanced features (advanced user). But at home, my dad use the sprinkler every day for manual operating (basic app user) and one day he asked me “what water level means”, understanding it like a sensor over a water tank, or something related with literaly water level.
In spanish, for a better undestanding should be something like “Factor de Riego” or “Factor de Tiempo”. Just like time or watering factor. For anyone who reads thats knows exactly that it is a multiplier of time.