Not a lot of cities use chlorine any more they use chloramine and this wont evaporate off so its in your tap water , get the best quality water you can R.O. is the best , then distilled , then tap water it has the most shit in it for plants but it will work , you want the lowest ppm in the plain water you can get your hands on, it makes a huge difference , 300 ppm of nutes to r.o.water is 300 ppm and 300 ppm to 250 ppm city water is 550ppm total get the picture you loose a lot of control as to what your plant is fed.p.s Walmart sells distilled water with 0 ppm for .97cents/4lt jug .