How to get SMS on mobile when Water tank has reached certain level

I want to make a simple project where,i can get sms alert once the water in tank reaches cetain level(Empty & Full). What is the required hardware and Steps. Any refrence,resource or guidance would be of great help

Or, if you have WiFi coverage at your tank you could try something like http://www.instructables.com/id/ESP8266-to-IFTTT-Using-Arduino-IDE/

arduino_x:
That's retired.

Sod off
http://www.arduino.org/products/shields/arduino-gsm-shield-2

I thank all my friends for the help rendered. However if i use Ultrasonic sensor HC SR04 and simple 16*2 display to show increasing or decreasing water levels how good is that idea? but following points need to be considered

  1. Tank is Aprox 20 mts away.
  2. I want LCD display in my house.

If i keep Aurdino Board and ultrasonic Sensor above tank,how can i have lcd in my house? Do i need to connect long LCD display to board using long wires? or if i keep Aurdino board and display inside my house, can i connect Sensor over large distance using CAT cable?

Commercial products like washing machines tend to use floating magnets that pass reed switches to read water levels. You could rig something up and it'd be as simple as an open door sensor. Only info you'd have to send is that something happened at whatever levels you're interested in.
You could run long sensor wires and keep the mcu and everything else indoors. There's no reason to put anything other than the sensor out there. You could also explore a wireless option and run the sensor on batteries, which could last a very very long time since it only would need to wake up when it is triggered by water level changing.