It's easy to think of what water could symbolize if you merely consider the ways that we need water in our daily lives. The most important use of water is to quench our thirst. If it weren't for water, we would die. That is why water is used as a symbol of life in the Bible. There is a river of life described in the book of Revelation and Jesus talked to the Samaritan woman about water that would provide everlasting life. Of course He wasn't talking about literal water. He was pointing the woman to a spring of water that flowed from God Himself, the real source of life that extended beyond the physical to eternity.
We also use water to clean ourselves. We wash before we eat to avoid germ contamination. We bathe our bodies to eliminate the oils, dirt and odors that our bodies produce. The water in scripture also symbolizes cleansing. Our spirits produce unclean things just as our physical bodies do. Just as our physical bodies need cleaning, so do our spirits. We see this when the Priests symbolically washed themselves before serving before God in the temple. We also see this in baptism where water is used to symbolize the cleansing of our inner self. See, even water has a deep significance.