First, I took measurements with the LSM9DS0 taking measurements as quickly as it could. That is, ~100 Hz.
Here is the water tap open a bit.
Here is the tap fully open.
The detection algorithm is pretty simple: Once you have a reading greater than 6050, look for a reading less than 2500. Once you get less than 2500, look for a reading above 6050. Once you get past 6050, increment a counter by 1, and start looking for <2500 again, and so on. From each peak to peak (i.e., 1 count) is approximately 0.0657 L of water. Pretty fine granularity!