More than 6000 megalitres released from Chaffey Dam is unaccounted for, according to Water NSW.

The Peel Valley's recent water balance report breaks down where the water from the dam went during the 2018/19 financial year.

A picture of the Chaffey dam in 2010 when it was close to full capacity. Credit:Geoff O'Neill/The Northern Daily Leader

The 6090 megalitres represent 17 per cent of the total water released from Chaffey, or more than six months' worth of water for Tamworth. On an average year without water restrictions, the city uses 10,000 megalitres.

Water NSW is yet to explain where the water went. However, other water balance reports state the unaccounted difference could be due to "river evaporation, seepage, overbank flows and any measurement errors recording other components".