Stainless steel water bottles are known for their durability and non-reactive properties, which make them suitable for storing water for extended periods. 

1. In general, you can keep water in a insulated water bottle for a long time without any significant impact on its quality if the water bottle is properly sealed and the water is clean to begin with.

2.Unlike certain materials, such as plastic, stainless steel vacuum flask does not leach chemicals into the water. 

Therefore, you don't have to worry about the stainless steel mug affecting the water's taste or safety. 

Stainless steel is also resistant to corrosion, rust, and staining, which helps maintain the integrity of the stainless steel tumbler over time.

3. However, keep in mind that even with a stainless steel sport bottle, it's essential to practice good hygiene and cleanliness. 

4.Regularly clean your coffee tumbler with warm soapy water and rinse it thoroughly to prevent the buildup of bacteria or odors. 

5.If you notice any signs of wear, damage, or a lingering odor, it's best to replace the insulated tumbler .

Additionally, if you plan to store water for an extended period, it's a good idea to store it in a cool, dry place away from direct sunlight, as exposure to heat and sunlight can potentially promote bacterial growth or affect the water's taste.