global GPIO
import RPi.GPIO as GPIO
import time

GPIO.setmode(GPIO.BCM)

GPIO_TRIGGER = 18
GPIO_ECHO = 24
GPIO.setup(GPIO_TRIGGER, GPIO.OUT)
GPIO.setup(GPIO_ECHO, GPIO.IN)

def get_water_level():
    GPIO.output(GPIO_TRIGGER, True)
    time.sleep(0.00001)
    GPIO.output(GPIO_TRIGGER, False)
 
    startTime = time.time()
    StopTime = time.time()
 
    while GPIO.input(GPIO_ECHO) == 0:
        startTime = time.time()
    while GPIO.input(GPIO_ECHO) == 1:
        StopTime = time.time()
 
    TimeElapsed = StopTime - startTime
    distance = (TimeElapsed * 34300) / 2
 
    return distance

print(get_water_level())