There's no alternative for pure water.
Why you should filter your water?
What most of us can think of as clean is not yet “clean” drinking water that runs from the well. It passed through miles of pipeline along the way, gathering pollutants and runoff. It is also likely to have been disinfected with substances that can leave behind carcinogenic by-products. (One important point to note: disinfection is a necessary evil, and a persistent concern will be waterborne infections without it.)
Only because your tap might have trouble does not mean that you could instead stick to buying bottled water. The demand for bottled water is virtually unregulated, and even the EPA states that it is not inherently cleaner than tap water. Plus, bottled water is bad for the environment: according to The Pacific Institute, about 17 million gallons of oil go into a year’s worth of plastic bottles. What’s more, nearly two-thirds of those bottles would end up in landfills or ultimately find their way to the ocean, polluting rivers and damaging wildlife.