Water that you drink might seem clear but might not be pure enough. There is a huge difference between clean and pure water. People drinking tap water after boiling it might think it as the best source of water but rather it just removes the substances from water making it look clean. There still might be some little impurities that can harm your health. Water that is treated by the kitchen water filter can actually be called as a true source of pure water and you can buy them here https://cleanairpurewater.com/kitchen_water_filter.html.
Clean water is just the regular water that is free from any kind of substances such as sand and silt. Some of the small microorganisms, true chemicals can also be found in water but the clean water is free from such bacteria and organisms. Though this water is still fine to be drunk but not extremely safe. Moreover by drinking clean water you can be safe from some kind of water related issues but cannot guarantee a complete safety.
Whereas purified water from the filter has an inbuilt process that can treat your water and make it 99% safe for drinking. It removes all the major chemicals, microorganisms along with heavy substances like led or magnesium. These substances and bacteria are likely to cause major stomach infections and illnesses.