How long should you water plants from the bottom? All you need to do is set the potted plant (be sure it has drainage holes) into the bathtub, sink, or another container that's filled with a couple inches of water. After 15 to 20 minutes, the plant will have absorbed the exact amount it needs—never too little or too much.
Is tap water bad for plants?
Most tap water should be fine for your houseplants unless it is softened because it has salts that can build up in the soil over time and eventually cause problems. Chlorinated water is also safe for most houseplants, but if you have a filtration system, that's even better for your plants.