There are two different theories behind the fountains. Some say they were used to supply drinking water to the people of Machu Picchu [1], and others say that they were ritual baths.
The fountains have two very distinct styles. The first three fountains are constructed in fine stone, and the rest are built in a more rustic style using stone and mortar. Walk down 10 steps, where you will see a small entrance to the right that will take you to the impressive natural cave, which the Inca fashioned into the Royal Tomb [2].
Links:
[1] http://www.moon.com/destinations/peru/machu-picchu
[2] http://www.moon.com/destinations/peru/machu-picchu/ruins-tour/royal-tomb-and-the-temple-the-sun