The Water District is part way a multi-year process to change the water meters at each premises. More than 50% of meters are new, and now read in cubic metres (m3), which is the same as 1000 Litres and equivalent to roughly 220 Imp Gallons. (2019.9692 to be exact)
Old meters read in Imperial Gallons. To calculate water use with an Old Meter simply read the number and subtract the latest Meter Reading stated on your last bill.
New meters read in cubic meters if you include the decimal point, or Litres if you use all of the displayed numbers ignoring the portion of register in Black. The picture below shows a reading of 0.251 m3, or 251 Litres. This is the same as 0.251 m3 x 219.9692 = 55 Imperial Gallons (or 251 Litres x 0.2199692 = 55 Imperial Gallons).
To calculate water use with a New Meter simply read the number, noting the Decimal Point and the numbers in Black portion of register, and subtract the latest Meter Reading stated on your last bill. Then multiply by 220.