There are reservoirs, and then there's the Ultimate Direction reservoir. It's made from a true "hydration...keep me drinking" company that has the know-how and engineers to make things work for any performance activity. It's made from premium materials and is easy to fill and clean.

If the reservoir is used for anything other than water or if it just needs a cleaning, wash it with warm, soapy water. Rinse it thoroughly and hang it upside down to dry. The Roll-Top can be rolled back to create a larger opening for faster drying. To remove a funny taste, wash it with a baking soda solution or with lemon juice. A word regarding iodine: iodine used to purify water will leave a red tint in the reservoir. This does not affect performance.
To help prevent valve freeze-up in a reservoir hose, store it with the valve up. The insulated hose and insulated contoured hydration pocket included with all Ultimate Direction reservoirs will help in cold weather. Keep water flowing to prevent the hose and valve from icing up. Just keep drinking. Then blow back through the valve to force the water back into the reservoir where it's less apt to freeze. Wear one of the flat packs under clothing to keep the fluids insulated. Run the tube under the arm and through a jacket for additional prevention.