Fiqh-us-Sunnah Volume 1, Purification and Prayer, Fiqh 1.014.

If there are impurities on the ground, it is purified by pouring water over it. This is proven by Abu Hurairah’s hadith, mentioned earlier, about the bedouin who urinated in the mosque. The Prophet, upon whom be peace, said all that needed to be done for purification was to pour water over it. Said Abu Qulabah, “The drying of the ground is its purification.” ‘Aishah said, “The purification of the ground is its becoming dry.” (Related by Ibn Abi Shaibah.) This, of course, refers to the case where the impurity is a liquid. If the impurity is a solid, the ground will only become pure by its removal or decay.