The best replacement for filtered water is tap water.

The best alternatives to filtered water are rated as following:
★★★★★  tap water
★★★★★  bottled water
★★★  distilled water
★★★  spring water
★★  distilled
★★  boiled water
★★  reverse osmosis
★★  purified water
★  soft water
★  alkaline water
★  nursery water
★  bottled
★  tap
  ionized water
  non filtered water

Your alternative for filtered water is not listed? Suggest!
Speaking about filtered water, one probably shouldn't forget about instant hot.

Other search terms related to filtered water and their ratings are:
★★★★★ instant hot
You have in mind a companion for filtered water and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of filtered water in all years. Click on graph for more.
filtered water
tap water
bottled water