Do you hold a water bottle when you run?

I don't take water for anything less than an hour and a half. Actually, I never take water, but on my longer runs, I loop back to my car about once an hour for a sip. For a 30 minute run, you should be fine without water. However, like others have said, a belt is your best bet. I'd also recommend an arm band for that phone. I can't imagine carrying my phone instead of wearing it :-)

Several possibilities:

Nathan Hand-Held. It's a water bottle with a strap that goes over your hand so you don't drop it. Strap has a pocket that might fit your phone.

Water belt. Come in many varieties, from ones that carry one regular-sized bottle at your back, to many little bottles arranged around you to distribute the weight evenly. Many have pouches to carry keys, gels, or whatever.

Bike jersey with pockets in the back. If the pockets are deep enough (they usually are, except for one of mine), one of the smaller flattish bottles that goes with the water belts I mentioned above will fit snugly at the small of my back. The pockets are also great for gels (or other snacks), keys, or whatever you need to carry.

Hydration pack. Again, lots of variety. These hold a bladder of water on your back, and are really meant for when you're going to be out for hours. But they can also be useful for 1-2 hour runs when it's miserably hot out. Most also have pockets.

Some people also park their car where they can run loops that pass it every so often, so they can stash water in their car. Or do the same with their house. Or carry money and design their route to run past a convenience store. Or run in parks where there are water fountains. Lots of possibilities!

I wonder why people feel the need to question why she wants to bring water or tell her she shouldn't "need" water.

The general public has been fooled into thinking that they NEED to have fluids during exercise, when the reality is that the body is designed to dehydrate during work bouts and then to replenish itself afterward, usually at meal time. The suggestions about hydration that have been made in the "Gatorade Era" have all come from studies that were backed by the large beverage companies. The studies have been poorly structured and the ensuing data has been interpreted to coincide with the beverage industry's agenda. It has been until relatively recently that these findings have been challenged by true exercise physiologists. Their persistence in this venue got the recommendation to "drink as much as is possible" change to "drink to thirst". This was within the last decade.

I suggest that you search for "Tim Noakes - Waterlogged". His book exposes this in great detail. There used to be a nice excerpt from the book on Running Times website, but when they merged the website with Runner's World, I lost it. So, you're own your own to find it. It's out there.