Auckland's water supply is at its highest level in 13 years, as months of downpours have filled lakes to their brim.
The lakes and dams from which Auckland takes its water are 99.8 per cent full, at least 15 per cent higher than usual for this time of year.
The dams in the Waitakere Ranges and Hunua Ranges which provide 80 per cent of the city's water, are officially 100 per cent full.
Watercare Services spokesman Daniel Wrigley said two months of high rainfall levels had completely replenished the water catchments for the first time since 1998.
"The combined capacity is 100 billion litres, so its fairly infrequent that they're all full," said Mr Wrigley.
National Institute of Water and Atmospheric Research records released yesterday show that Auckland's rainfall during July was near-normal.
But in the previous six months, , rainfall was above average every month, especially in April and May.
Mr Wrigley said the high levels gave the city water security if it experienced a dry summer.
"It's significant in summer - it means we've got more reserves, so the likelihood of us having any issues with water supply decreases.
"If our lakes are so full up here, it means we don't have to bring so much supply up from the Waikato."
But it does not make the water cheaper for residents, because the cost of pumping the water to homes does not decrease when lakes are full.
Water now costs homeowners $1.30 for 1000 litres.
The high storage levels are a dramatic turnaround from early last year, when low rainfall raised the possibility of water restrictions.