All perfect praise be to Allaah, the Lord of the worlds. I testify that there is none worthy of worship except Allaah and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
It is obligatory to wash the feet, as well as the other body parts of Wudhoo’, completely in the first time of washing, to the effect that nothing should remain that hinders water to flow on the skin. Then the two other times of washing are recommended. This is the perfect way of washing. As for the sufficient way, it is enough to wash every body part only once.
Thus, as long as the questioner poured the purifying water over his feet and washed them completely, the change of the color of water as it flows over the feet or as it drips from them is of no consequence. In principle, the dripping of water from the body parts is not conditioned. Rather, the flowing of water over the body part is a prerequisite and because the non-solid impurity is not considered a separating medium.
Consequently, it is not required to wash the foot until drops of pure water drip from it. Ad-Dardeer, may Allaah have mercy upon him, a Maaliki scholar, said: "There is no minimum amount for the water (which should be used in Wudhoo’). Dripping of water from the body part is not conditioned; however, its flowing (on the body part to be washed) is a prerequisite." Ad-Dusooqi, may Allaah have mercy upon him, a Maaliki scholar, said: "The type of dirt which should be removed in Wudhoo’ is the solid dirt, such as mud. As for the dirt which does not make a barrier for the water, its removal is not required in Wudhoo’."
Accordingly, it is clear now that dripping of pure water is not conditioned in Wudhoo’. It is permissible for one who performs Wudhoo’ to clean the feet to the extent that the dripping water is pure, whether one performs Wudhoo’ by pouring water with his hand or directly under the faucet, as long as he does not waste water by washing more than three times or needlessly uses an excessive amount of water.
Allaah Knows best.