Carry plenty of fresh water. If you are familiar with the area in which you are traveling, and can be sure that water sources are available, carry enough water to get you there. If you aren't bringing your water from home or a public source, treat the water you draw from the backcountry, regardless of the source. These days, everything is suspect. Use water filter, purifier, chemical tablets, or boiling to treat the water before consuming.
Some folks use other containers such as old plastic pop bottles.
That's okay too. A better choice would be a pealess plastic whistle like the Fox 40. It is ultra-light and very shrill. REI sells em. Since the first option doesn't cut it, there are numerous commercial repellents on the market.