Movement in 1 foot of water?

[johnsemlak]

What are the exact rules for moving in about 1' or so of water? Is it considered 'difficult terrain' and simply 1/2 movement?

 

[Hand of Evil]

Difficult terrian for medium sized creature.
Learn to swim for small or tiny.

But from the SRD - Wilderness, terrian, enviroments.

Pool: Pools of water collect naturally in low spots in dungeons (a dry dungeon is rare). Pools can also be wells or natural underground springs, or they can be intentionally created basins, cisterns, and fountains. In any event, water is fairly common in dungeons, harboring sightless fish and sometimes aquatic monsters.

Pools provide water for dungeon denizens, and thus are as important an area for a predator to control as a watering hole aboveground in the wild.

Shallow Pool: If a square contains a shallow pool, it has roughly 1 foot of standing water. It costs 2 squares of movement to move into a square with a shallow pool, and the DC of Tumble checks in such squares increases by 2.

Deep Pool: These squares have at least 4 feet of standing water. It costs Medium or larger creatures 4 squares of movement to move into a square with a deep pool, or characters can swim if they wish. Small or smaller creatures must swim to move through a square containing a deep pool. Tumbling is impossible in a deep pool. The water in a deep pool provides cover for Medium or larger creatures. Smaller creatures gain improved cover (+8 bonus to AC, +4 bonus on Reflex saves). Medium or larger creatures can crouch as a move action to gain this improved cover. Creatures with this improved cover take a –10 penalty on attacks against creatures that aren’t also underwater.
Deep pool squares are usually clustered together and surrounded by a ring of shallow pool squares. Both shallow pools and deep pools impose a –2 circumstance penalty on Move Silently checks.

Special Pools: Through accident or design, a pool can become magically enhanced. Rarely, a pool or a fountain may be found that has the ability to bestow beneficial magic on those who drink from it. However, magic pools are just as likely to curse the drinker. Typically, water from a magic pool loses its potency if removed from the pool for more than an hour or so.
Some pools have fountains. Occasionally these are merely decorative, but they often serve as the focus of a trap or the source of a pool’s magic.

Most pools are made of water, but anything’s possible in a dungeon. Pools can hold unsavory substances such as blood, poison, oil, or magma. And even if a pool holds water, it can be holy water, saltwater, or water tainted with disease.