Water is simple until it is not. Carry too little and the walk becomes uncomfortable. Carry too much and your pack feels heavier than necessary. For UK day hiking, the best setup depends on route length, temperature and whether you can refill safely.

For most day walks, one to two litres is enough. In cool weather on a short route, one litre may be fine. In summer, on long climbs or exposed routes, carry more.

Hard bottles are simple and reliable. You can see how much water you have left, they are easy to clean and they fit side pockets. A one litre bottle on each side of the pack is a straightforward setup.

Hydration bladders make drinking easier while walking. This is useful if you forget to drink regularly. The downside is that they are harder to clean, harder to refill quickly and you may not notice how much water is left.

Soft bottles are popular with lightweight hikers. They pack down when empty and work well with filters. They are less durable than hard bottles but very convenient.

A flask is worth considering in winter. A hot drink can make a cold wet lunch stop much better. It adds weight, but comfort matters on long winter days.

Water filters are useful for backpacking and remote routes, but they are not always needed for day hikes. If you plan to drink from streams, understand the risks and choose a proper filter or purification method.

Do not rely on cafes, taps or streams unless you know they are available. Many UK routes pass through villages, but many hill routes do not.

The best setup for most UK hikers is simple: one or two bottles, easy access, and enough capacity for the day. Add a filter for longer or remote routes. Add a flask when warmth is worth the weight.