only if your plants like all the shit that comes out of your faucet.. Arsenic at my last house, lead, chlorine just to name a few.. Last place I used a 6stage ro/di system and I filter every single impurity out and get a clean reading of 0ppm before I mix any nutes or PH the water..... Some places Tap water is fine..(as long as you PH it..) mine here is running about 90ppm and 8.6PH so the ppm realy isnt bad I can lower the PH I need to check online for the recent water analysis for my area though..