Drink more water in a cup

How about a cooler? Ice in a cooler lasts for days. I used one in my jeep when I went to Texas. You can also freeze water bottles. The plastic ones. Take out as needed. Fruits like watermelon, cantelopes, and the like are mostly water. Best wishes.

Someone mentioned Yeti, I second that.
Ice will stay for hours.

Fill your thermal water tumbler (Yeti or otherwise) with ice and keep adding the water to it through the night…? The ice will keep all night long.
Or, fill a plastic water bottle about 1/3 of the way, lay it on its side in the freezer (I usually tilt it at a diagonal) and just top it up with water once it’s frozen….take those to bed with you (You can do multiples if you need to)

You could buy a steel insulated container and chill the water in that and drink from it. It will keep water cool a long time. Add some ice to the water to keep it even cooler for a longer time.

“All the way downstairs ?” . Never heard that distance referred to as “all the way” unless you’re talking about a 6 floor walk up .

room temperature is better then ice cold

Freeze half filled bottles of water and ad water to them as needed should last you a few hours.

Like others have suggested, an insulated drink container will work well and be the the cheapest and easiest approach

My kid and wife both use those YETI insulated containers and they seem to keep things cool for hours and hours.

a yeti will keep water cold for a pretty long time

A little lemon in the water if it is not contraindicated

I have a tabletop ice maker, would that work?

Maybe see if you can find a small insulated bag you can put ice In

Well why not get one of those britta water bottles and run the tap till cold water flows and refill you water bottle when it gets too warm!

My yeti keeps my water cold a long time.

Maybe a cooler

If it's cool outside, and there is a ledge outside the window, put bottles out there.

Mini fridge

thats not good

A tap

Dorm/hotel fridges don't really take up a lot of space, they are light enough they can sit on top of an end table. Here is one for less than $100 you can have shipped free to your local Walmart to pick up there.