leaves dying, tap water?

How bad is watering a plant with tap water? I have three plants growing, never seemed to cause any issues watering with tap water until deep into the flowering cycle, I have a plant that is about ready to harvest and in the past two weeks the leaves coming out of the buds have started to die and crisp up. Is this a tap water issue perhaps? Lack of nutrients? (Im in the flush cycle). Im doing this grow a very newbie way, no idea what the pH of the water or soil is, no clue as to the grow room humidity and the general grow room temp is "warm". I realize I should buy pH and humidity testers etc but does anyone have a general idea of what causes these symptoms? The plant is about 14 inches from a 400 watt HPS lamp

If you are close to harvest expect your leaves to start dying off especially if you have flushed. The buds have no nutrients left in the soil to use and are using the leftover nutrients in the leaves for energy. This is perfectly natural and will lead to a better smoke as you dont want all them nutes left over when you harvest. Now if the buds are also affected you might have a problem but being so close to harvest there is probably little you can do to fix the problem. Good luck and next time get an all in one thermometer/hydrometer and a ph test kit from your local pet store.

As far as your question goes about using tapwater the only way you or anybody else for that matter can know is if you tested it. Most people use tapwater and let it sit for 24 hours so the chlorine can bubble out. Tapwater is good because it has calcium in it and most bottled water from the store lacks it. Like I said, only way to know is to test it

if you are in the last 2 weeks and started flushing that would be normal, but if you are flushing i would suggest you use clean purified water because tap is usually around 7 or up and you want your level to keep dropping ,not staying at 7