Canterbury’s drinking water
Canterbury has some of the best drinking water in the world, but no water supply is completely without risk.
Water can be contaminated by bacteria, viruses, nitrate, metals and other chemicals. Some contaminants occur naturally, while others come from human activities. If you’re on a reticulated supply, your local council or water supplier will assess those risks and make sure your drinking water is safe. If you have your own well, the responsibility rests with you.
Who helps ensure our water is safe to drink?
- Local councils are responsible for the supply, distribution, treatment and safe supply of drinking water.
- Environment Canterbury’s role is to monitor and test our drinking water and protect it at its source.
- The Ministry of Health appoints drinking water assessors who are employed by the Canterbury District Health Board to oversee the impact of water quality on health.
Getting your drinking water from your own private well?
People with private drinking wells are responsible for ensuring their supply is safe.
If you get your drinking water from your own private well, there are some things you should know and do:
- Make sure you know where your well is and that it’s in good condition
- Ensure your well head is secure and clear of any debris and fenced off from animals
- Regularly test your water by taking a sample and sending it to a lab for analysis (at your own cost)
- Check the historical use of the land to understand the contamination risks
How to protect your private well head
Learn about practical information and tips on how to protect your well head (PDF File, 1.06MB)
Find out more about drinking water safety.
Christchurch’s drinking water
Our main urban area, Christchurch, is blessed with a plentiful supply of fresh clean drinking water. Environment Canterbury works with the community to help ensure we protect our fresh water now and for generations to come. People from across our region are working together as kaitiaki to protect and improve our water resources.
Around three-quarters of Christchurch’s groundwater comes from the Waimakariri River to the north of the city. The rest comes from rainfall to the west and north of the city. The water from the river and rainfall seeps into the gravels and flows towards the city at up to 25 metres per day.
Downstream of this point, some of the water in the river begins to flow into the gravels of the plains, topping up the aquifers on which Christchurch depends for its drinking water.
Environment Canterbury owns a significant amount of land in this area. The land is managed to ensure it is used for appropriate purposes that won’t have an adverse impact on Christchurch’s groundwater.
Flowing through the gravels at about 25m a day, groundwater takes a few years to reach the zone from which Christchurch takes its drinking water.
Christchurch’s groundwater supply is famously pure at its source but the most serious threat to groundwater quality is development (industrial, agricultural and commercial) over the zone.
Christchurch’s drinking water is protected by rules in the Canterbury Land & Water Regional Plan which controls land-use to minimize the risk of contamination. Much of the area is used for very low intensity stock grazing and recreational parks.
Let's look at the (aqua)facts around Christchurch water
All Canterbury city and district councils are involved with protecting our water via the Canterbury Water Management Strategy, but three agencies are directly responsible.
Environment Canterbury looks after the source of our drinking water (aquifers, rivers and lakes); local councils are responsible for the supply, distribution, treatment and safe supply of drinking water (the infrastructure) and the Ministry of Health through the Canterbury District Health Board monitors the impact of water quality on health. Watch the video for more information or read through our pages on Canterbury's drinking water.
There is no risk of running out. Christchurch’s water supply is well understood by scientists and is sustainably managed. 123 billion litres of rainfall onto the areas north and west of the city, and 252 billion litres which ‘leaks’ from the Waimakariri River recharge the Christchurch aquifers each year.
In total, that's about 375 billion litres or 150,000 Olympic swimming pools which flows through the Christchurch aquifers each year. What isn’t used ends up in the ocean.
Nitrate levels are an indicator of water quality. Elevated levels can indicate the presence of compounds which may cause health issues. We know nitrate levels will increase over time due to poor land-use practices in the past.
Christchurch’s drinking water has about 1mg of nitrate per litre and strict rules are in place to keep our water at a safe level. The maximum national health level is 11.3mg per litre.