Waitaki District Council water services and waste manager Martin Pacey told a council meeting in early November people were tampering with council water supplies and it was costing "quite a lot of money".
"It is becoming more and more of a problem."
In an emailed response to questions, Mr Pacey said water theft occurred at all council water supplies, however, in the past month several illegal connections were identified in the Enfield area of the Oamaru water supply.
He said council contractors identified the illegal connections while investigating a no-water complaint in the area and these were being followed up by the police.
Mr Pacey said water theft had affected the operation of rural restricted water supplies for several years.
"The number of identified incidents, however, appears to be on the rise despite council’s efforts to deter water theft through its Water Supply Bylaw, adopted in 2014.
"The increase seemingly correlates with changes to more intensive farming practices placing greater demand on allocation and, subsequently, more frequent inspection programmes by council."
He said water theft cost ratepayers.
"Treated drinking water can cost more than 90 cents per cubic metre to produce and supply to consumers. Therefore, when individuals take additional volumes of water outside of the allocation for which they pay, the cost to supply that falls back on all ratepayers."
For the council’s restricted water supplies, water theft could cause a pressure drop in the network which could affect the supply of water to more elevated properties.
In such instances there were significant costs involved with rectifying this. Costs included temporarily carting water to affected consumers, contractor and council officer time in investigating the cause of the issue, and council enforcement officers’ time in following up the illegal incidences with the police.
He said Waitaki records showed on average 9% of connections were tampered with annually. In 2016 alone, about 40 cases of water theft were investigated and rectified.
The closest profile council had for a water thief was built on the fact that water theft predominantly occurred in the rural sector with the general motive of economic gain.
Water was typically stolen at the consumer’s point of supply and, on rural supplies, the most common illegal act was the removal of the council restrictor, designed to deliver a set volume of water to a property based on the allocation paid for. Also common was the installation of a connection ahead of the restrictor device.
Mr Pacey said it was difficult to ascertain just how much water went missing from council’s supplies.
