Cleaning a water reservoir is pretty essential for preserving its overall health and durability. At first pour, some warm water inside flushes the hose and let it out. Use mild soap and scrubbing brush and scrub the interior surface as much as you can reach. Again add some warm water and a pinch of bleach along with 2 tablespoons of baking soda. Close the lid and leave it for half an hour. Now rinse it thoroughly with normal water. You can use some lemon juice too in your cleaning solution.