The Shaykh (Al-Mufid), may Allah سبحانه وتعالى support him, then added: "Water falling onto the ground, clothes, or body during ablution does not harm the one performing Wuduʾ, as it remains pure. Similarly, water falling on a clean surface after being used for Istinjaʾ (cleansing after using the restroom) and then splashing back does not make the clothes or body impure unless it falls onto visible impurity and carries it back. In such a case, one must wash whatever was touched by the contaminated water."
Commentary #36