Merging of two functions
Functions like 

boolean Water_Level_Check_A(){
   boolean Result = digitalRead(Water_Level_A);
   return Result;
}


Are really overcomplicated. You're just calling one function and returning that value, so it can be simplified to 

boolean Water_Level_Check_A(){
   return digitalRead(Water_Level_A);
}


Or just the expression 

digitalRead(Water_Level_A)


whenever you need it. 

So all you're doing is calling digitalRead() on a pin number and check if the result is low. If you really want to move this to a different function then you could give it the pin number argument and directly invert the result so that a true from this function means that some action needs to be done.

boolean Water_Level_Check(int sensorPin){
   return !digitalRead(sensorPin);
}


And then call it as 

void loop() {
   if (Water_Level_Check(Water_Level_A)){
       //--&gt; Water Pump A
   }
   if (Water_Level_Check(Water_Level_B )){
       //--&gt; Water Pump B
   }
}