This is a reasonable question. I have used new plastic bottles to collect spring and artesian water in several locations. In filling, I completely filled and capped to minimize air and stored for months until drinking, typically keeping than out of sunlight in my home. I have not become sick to my knowledge of this, and have not done it as a regular practice. If I had a spare referigerator, I would have stored them to keep them cool. But I can see where this may not be a responsible practice.
I do not understand your question, you want to keep the water from the source at room temperature in a plastic bottle: for drinking or for water testing later ???
To complete some physicochemical analyzes and / or isotopic or even microbiological there is a conservation of period to respect (period required between sampling and the start of the analysis).
Spring water (cold/ hot ) if keep for long time ( even in week time )may change its chemical/ physical )characteristics. For example pH , EC and TSS are much effected.