As a population explosion engulfs Queenstown and Wanaka, local councils and water scientists are fighting a race against time to protect the Southern Lakes' pristine waters from urban run-off.
Wanaka is a township characterised by the arid Central Otago landscape - golden brown peaks stretching down to tawny plains surrounding a pristine, sparkling lake.
But its beauty and serenity is drawing new residents from northern climes - some of whom are planting sub-tropical gardens that require constant irrigation and fertilizing.
Lush, green lawns on brand new subdivisions now sit opposite tawny council grass street verges, and when it rains, fertilizer from those lawns could end up in Lake Wanaka.
In nearby big brother Queenstown, with jewel-in-the-crown Lake Wakatipu, tourists and residents battle it out in traffic jams that would frustrate even a hardened Auckland commuter.
Both towns are undergoing rapid urban development, with business parks, subdivisions and airport expansion projects underway.