Arrakis would not be our tourist destination, for sure. We like our baths way too much.
Water is perhaps the most valuable resource on Arrakis, even more valuable than the spice. We can see this importance in every detail of the Fremen culture. To obtain as much water as they need to survive, the Fremen have developed stillsuits to prevent the body from losing more than a thimble's moisture a day. Their people show their loyalty to their tribe by sharing the bond of water. They even strain their dead to salvage the water from the cadaver. The details are a little sparse, but we're going to guess, um, giant juicer with pulp extractor.
The X Factor
But what does water symbolize? Well, how about, um, anything? It may seem a broad answer, but it's an apt one. Let us explain.
An ecological system is determined by the things within it. In a way, the rarest of things within an ecological system define that system more than things it holds in abundance. For example, Alaska has a vast and beautiful wilderness, but what have people going to Alaska historically been obsessed with? Something extremely rare: gold. The same works with water in Arrakis. The Fremen obsess over water because of its rarity. Bewt the waterseller makes his fortune on being able to produce this rare substance. He cashes in on supply and demand.
So, water can symbolize almost any rare substance found in an ecological system. It all depends on which system you want to compare it to. If you compare it to the Middle East, water could symbolize oil. If you compare it to America, water could represent money. What about the Somalia starvation crisis? Water is a suitable symbol for any scarce resource in an ecological system.