From Broken Hill in outback NSW to the coastal city of Cape Town in South Africa, the issue of water availability and rainfall is headline news.

But many Sydneysiders may have forgotten that 10 years ago this month, the city was facing its own water crisis – and as our analysis of the recent dry spell shows, conditions can change quickly. So which suburbs get the least amount of rain – and could Sydney face another water crisis?

Dam levels in Sydney catchment OR percentile rainfall ranking by BOM.

The south-west of Sydney has seen about half the rain of northern and coastal areas in the past nine months, while across the entire Sydney basin, low rainfall and above average water use have pulled dam levels down more than 17 per cent since June 2017.

Sydney's water crisis peaked 10 years ago when dam levels fell below 34 per cent. It was announced that a $2.3 billion desalination plant would be built to make sea water drinkable. Despite costing every Sydney Water customer about $100 per year to sit idle, that plant has not run for more than five years and won't be used unless dam levels drop to 60 per cent. IPART recently decided to reduce this fee to $85 if it stays idle and $135 if it is switched on this year.