Is pool water considered pure if it touches clothes, taking into account that children may swim in it and could cause it to become impure?

The fundamental principle for all water is purity, unless its color, taste, or odor changes due to impurity that has fallen into it. In such a case, the water is deemed impure, whether it is little or much. This is based on Allah Almighty’s saying: "And We sent down from the sky pure water" (Quran 25:48), and the Prophet, peace and blessings be upon him, said: "Water is pure; nothing makes it impure." Accordingly, pool water remains pure until a change due to impurity is certain. If the purity of the water is certain and there is doubt about its impurity, one should perform ablution with it, because the original state is its continued purity.