The management of drinking water quality is crucial to the prevention of waterborne diseases and chemical contamination. Most of metropolitan Christchurch's drinking water is "aged water" from underground aquifers, and as such does not generally need to be treated to make it safe for human consumption.
After the February 2011 earthquake, the water supply was chlorinated for a period to control the risk of cross-contamination from damaged sewerage and water supply infrastructure.
At times of peak demand during the summer, restrictions may be placed on water use. In the long term, Christchurch needs to manage demand for water in order to ensure security of supply.
Read the full issue summary for drinking water [PDF] - updated August 2016.