Hi I bought a this plant yesterday and it said it was a dracaena but when I looked online the one that looked like it was the dracaena warneckii and I was wondering if it was that one. I also heard you can't give it tap water is this true. Thank you.

Lagn!
It does appear that it could be... Striped Dracaena (Dracaena fragrans 'Warneckii')

As far as tap water goes... If you do use it straight from the tap, you could notice that the leaf tips start to brown. Mostly due to the fluorides and such in the water. A lot of people use distilled for their plants, but I've not had too much trouble with tap.
Though I do let my jugs with tap sit at least 24 hours before using.

Terrafirma thank you for the information one more question should I use fertilizer once a year or twice.

Most of your houseplants can be fed about March through October, when good growth is coming on. Pull back some in the winter in watering, and I usually withhold feeding in the winter months also. If you're using a liquid/water soluble fertilizer, I'd suggest half the recommended strength once or twice a month.
Keep an eye out for buildup of salts. That can also cause the brown tip of leaves. You may find this article interesting... http://garden.org/ideas/view/L...

I use more control release fertilizer in my own houseplants, just because I find it to be less messy. There is a good article here about them... http://garden.org/learn/articl...

Good luck!
Happy gardening!