The health of a water distribution system is commonly gauged by a statistic known as Unaccounted for Water (UAW). It is normally expressed as a percentage of the total volume withdrawn during a given year. The volume lost is the difference between the volume withdrawn and the volume that is accounted for.
The easiest way to account for water is through billing. All of the servcies in Topsfield are metered and we can quickly calculate the total volume of water billed in a year. The billing cycles for two-thirds of our customers do not match the calendar year but the differences occur in the winter time when water use is generally lower and more likely to be consistent from year to year. The Department of Environmental Protection allows us to also account for water use that can be 'confidently estimated'. Estimated use includes water used for fire fighting & training, hydrant flushing , water main breaks, drain cleaning and street sweeping.