Historical values of Unaccounted for Water (UAW) for Topsfield are listed below.  Beginning in 2006, DEP requires UAW be kept below 10%.  We were able to do this for several years but in 2009 UAW jumped to 11.5% despite annual leak detection surveys.  We conducted an extra round of leak detection during Fiscal Year 2010 & 2011 to compensate for the increase.

We lost 7.16 million gallons of water during 2011 or 13.6 gallons per minute.  If the leakage were the only reason for the loss, we would be looking for a single hole slightly less than 5/16 inch diameter or up to twenty-four 1/16 inch leaks.  Large leaks are easier to find because the water will surface or the noise created by the water escaping from the pipe can be heard by a trained leak detector with the proper equipment.

 

Year Calendar

Withdrawn

Billed Confidently Estimated Unaccounted for Water Volume Unaccounted for Water Percentage
2001 194.898 175.484 Not available 19.414 10.0%
2002 169.706 147.004 11.100 11.602 6.8%
2003 172.704 135.801 12.200 24.703 14.3%
2004 146.916 120.545 14.271 12.100 8.2%
2005 161.786 121.372 8.415 31.999 19.8%
2006 148.893 130.267 8.147 10.479 7.0%
2007 152.827 127.529 11.468 13.830 9.0%
2008 140.640 125.730 8.180 6.430 4.6%
2009 143.470 118.756 8.274 16.440 11.5%
2010 146.732 122.076 10.366 14.290 9.7%
2011 140.045 123.772 9.113 7.160 5.1%
2012 as of 4/1 26.702 23.864 0.539 2.299 8.6%
All volumes are in millions of gallons