In recent years our annual water supply has typically varied between about 55-56,000 million litres, or just over 1,000 million litres in an average week. If Wellington's Westpac Stadium were a reservoir, this weekly volume would fill it completely.
Our supply currently serves a resident population of around 380,000, so on average we provide about 400 litres per resident each day, or four bathtubs each. Not all of this water is used by individuals at home. Businesses, industry, schools, hospitals, councils etc all use water too.
The following graph shows the changing levels of water use at different times of the year and contrasts average daily supply with the highest daily supply each month.
The variability in how much water is used each year depends largely on the weather conditions we have during spring and summer and how much water is used outdoors, especially on gardens.
Over the course of a year, the average daily volume of water we supply is about 150 million litres. However, during periods of dry weather in summer, daily demand for water has peaked at almost 220 million litres or about 50% more than the average daily demand during winter months. Because our water supply comes mainly from rivers, which rely on rainfall, it can prove challenging to meet all demand for water during very dry summers.
For more information about water supply volumes see our latest Water Supply Annual Report which is located in our Plans & Publications section (see under Our Services).