They have desalination plants as well, which are petty expensive. In order to thwart invasion of saline water, they tried to pump ground water from these coral islands. The water was dark and little smelly. It was mainly used for washing purposes only. Maldivians have modernised the age-old indigenous practice of harvesting rain water.
Techniques are very simple.
They attach a water pipe with the roof. With the first monsoon shower, they wash the roof top by allowing the water pipe to different outlet. During subsequent rains, they harvest all rain water in a reservoir underground. This sweet water is used for drinking and washing purposes only. In this way they store plenty of sweet water minimizing the need of desalination plants.