Dracaenas are especially sensitive to fluoride, which doesn't evaporate.
http://extension.psu.edu/pests...
Specific species are mentioned in the above link, but I have 7 or 8 diff Dracs and the cause/resulting symptoms seem universal to me.
Everyone should know, at least 95% of pics that exist of perfect Dracs in pots were just trimmed just before the pic was taken. It's THAT difficult to keep the leaves all perfect, and bottom line, with the exception of a very few of the species/cultivars, there is no such thing as an old, woody Drac with perfect leaves from the tall tip to the soil surface. Like a palm tree with a pouf of foliage at the top, that's the normal appearance of most Dracs. The yellow/brown tip is the first sign a leaf has been designated for discard. You can start chasing the brown back with trimming, or take them off cleanly, pulling gently in a sideways direction, so as to peel the leaf from around the stem/trunk. Then it looks fine again, just like the pics, right? As long as new leaves are forming as fast as or faster than old ones are being discarded, it's considered to be doing just fine.
No way I'm buying water for plants either, I'd go broke. Distilled is very inexpensive, convenient if folks just have a few plants. Melted clean snow is equivalent to rain but also more effort than I'm into (when I lived in a place where there was snow, not an option here.) If you have a dehumidifier, the water it catches is free of minerals or tap water chemicals, as would be the runoff from an A/C during the summer. It's possible to catch rain all year here, but I use tap water sometimes too, convenience, and sometimes it doesn't rain for a while. Letting tap sit, to come to room temp, is good but won't help get rid of the chemicals like fluoride that can make plants ill if it builds up in the pot. As long as water doesn't sit in a drip tray, that build-up should be something you can avoid by using non-tap water when possible. An occasional or seasonal use of tap should be fine like that, what I do.
Sheryl, if you're at the point of getting rid, I wonder if it's been a while since repotting? If that seems like more effort than they're worth to you at this point, why not try putting in the ground? You've got the dryness to make it work if it can be done with what I'm assuming is just occasional light frost, 9B? My Mom's corn plant has been outside permanently for a few years. Last fall/winter, I went to move it to the garage for her but it was more than firmly rooted in the ground through the pot. Already more frost & lower temps than all last winter but her plant looks in no danger of death. Who knows if it can survive if we get a 9-degree night like a few years ago. I think it would come back from the roots if it was devastated completely above ground. If such is predicted, I'll pile some leaves around it for her. That's helped me cheat a lot of stuff before, though a pile of leaves might not be such a cavalier, casually available thing in AZ.