At some point if running long-distance, for me probably anything over 1.5 hours, you will need to get some water or other hydration at some point along your run. You could stash water, or go different distances coming back to your home or car in between to replenish, or you can carry it. I usually choose to carry it. I have two options to carry water while running, both work great and are preferred depending on where I am going and what else I am taking.
The first is a waist belt. I have this one. It works great – and I have had it for years and the velcro still holds. There is a pouch that can carry my phone, key, and a gel or two, and another smaller zipper pouch that could carry a key or a dog poop bag (or two). It also holds 4 8-ounce water bottles that come with the belt and fit well. You can of course bring fewer bottles if you do not need that much water; and Nathan makes similar belts with different configurations of bottles and pouches (I would rather just have the capacity if needed). The only downside to this is if I have other things around my waist – mainly my dog leash. It works, but sometimes I prefer my backpack for that reason.
There are a number of running packs on the market. I have only used one and I love it. It is designed to carry enough stuff for super duper long trail runs, which I may dream about someday but do not currently do. Still, it is light enough that it doesn’t bother me even to just carry a little water on a relatively short run. One neat feature of the pack I have is that it can carry water in the bladder, but it also can easily hold two of the little bottles that go in my waist belt. I have brought one or two of those for long runs when I want some electrolyte drink along with water. I prefer not to add flavoring to the bladder because I worry about cleaning it, so I bring a super-concentrated mini-bottle and take little sips along with water. [I should note that the pack I have is men’s. They are fairly expensive and I found this on a good deal when I was looking for one. I was worried that the chest straps were not particularly well placed for a women’s anatomy, and indeed it may look a little odd, but as far as fit and staying secure, it has worked well. I do not know the difference in design for their women versions].
I see other people running with a bottle that they carry in their hand, usually with a strap on their wrist. This doesn’t look appealing to me at all, but clearly some people do not mind it.
There are so many packs and waist belts and different options on the market, it can be a bit overwhelming. It was difficult for me just to find links to what I have because there is so much out there. My recommendation would be to not worry too much about it. My theory of getting more than what I need has worked well, and I have been happy with my first purchase in the belt and pack category and now I no longer have to worry about what’s on the market until one of them breaks, hopefully many years from now!