All the cities urgently needed town water supplies by the 1860s, and dams were built in the surrounding hills.
Dunedin had its first reservoir by 1867. Capacity was soon exceeded and in 1881 water was piped from the Silverstream catchment to augment the supply.
In Christchurch the Avon River and various pools were used to supplement rainwater. Residents also quickly took advantage of the gravel aquifers below the city by digging wells in backyards and building windmills to pump up the water. From 1863 the city council experimented with deep artesian wells. Public wells, complete with troughs, drinking fountains and pumps, were built. Reticulation of high-pressure water from council wells and a pumping station were proposed in the 1870s, but did not happen until 1909.
Wellington's first waterworks – the Karori reservoir – started operating in 1874. In 1884, the water supply was bolstered by supplies piped in from the Wainuiomata River in the Hutt Valley.
Auckland began piping water from Western Springs in 1877. By the early 1900s the Auckland City Council realised that it would need a long-term strategy to slake a growing city’s thirst. In the early 1900s the council built small, and then larger, dams in the Waitākere Ranges. With demand growing the council eyed up the larger Hūnua Ranges catchment. Much larger dams such as Cossey's Creek (1955) and the huge Upper Mangatāwhiri reservoir (1965) followed. Treated water from the Waikato River first supplemented the city’s water supply in July 2002 – more than 130 years after it was first suggested. In the early 2000s up to 75,000 cubic metres of Waikato River water was pumped through 38 kilometres of pipes each day, supplying around 10% of Auckland’s needs. The North Shore's water supply was originally drawn from Lake Pupuke, but switched to Auckland City’s system in 1945. Since 1959 North Shore City’s water supply line has run along the Auckland Harbour Bridge.
By the mid-1960s around 70% of the population was served by a public water supply. Most of the remaining households obtained water from springs, streams, shallow wells, artesian bores and roof catchments.
Most town water supplies had very little treatment – water was just piped from a river or lake. Treatment is mainly necessary to reduce the risk of microbiological contaminants such as giardia and cryptosporidium making people sick. Chlorination is the most common treatment method – a chemical compound is mixed with water to kill bacteria. Other common treatments are coagulation (making fine particles drop out) and filtration. Chlorination was introduced to many supplies in the 1950s, and fluoride was added to some in the 1960s to improve dental health. A 1960 survey of public water supplies using World Health Organization criteria rated 35% of supplies as ‘good’, 41% as ‘doubtful’ and 24% as ‘unsatisfactory’.
The Health (Drinking Water) Amendment Act 2007 amended the 1956 Health Act. Before this, 500,000 people had drinking water that did not meet New Zealand standards – which were voluntary. The act imposed duties on all suppliers to ensure that their water was safe to drink. Water is tested daily in large water supplies and monthly in small supplies.
Paying for water
In Auckland and some other cities, domestic water metering has been introduced. Meters measure the amount of water used, and users are charged for this. Most towns and cities do not have metering and water supply is paid for through council rates.
Urban drinking water also came under threat from a new source in the 2000s. The massive intensification and spread of dairy farming led to over-allocation of fresh water for irrigation in some places, and greater pollution of water sources.