The Christchurch City Council has begun chlorinating the Riccarton water supply.
The temporary chlorination of the Riccarton and north-west zones began on Friday, 6 April. The north-west zone stretches from Belfast through to Yaldhurst and includes parts of Riccarton and Addington and supplies 80,000 people.
The council is temporarily treating Christchurch's drinking water with chlorine while it upgrades below-ground well heads.