On the authority of ʿAbdullāh ibn Mughaffal, who said: The Messenger of Allāh (peace and blessings of Allāh be upon him) said: "Let none of you urinate in his bathing place, for most whisperings (from Satan) come from that." (1)

Abū ʿAbdullāh ibn Mājah said: I heard ʿAlī ibn Muḥammad al-Ṭanāfasī say: This applies only to a pit dug in the ground. As for today, their bathing places are made of plaster, mortar, and pitch, so if one urinates and then lets water flow over it, there is no harm in it. (2)

13 – Chapter: What has been reported concerning urinating while standing

305 – Abū Bakr ibn Abī Shaybah narrated to us, Sharīk, Hushaym, and Wakīʿ narrated to us, from al-Aʿmash, from Abū Wāʾil, from Ḥudhayfah: That the Messenger of Allāh (peace and blessings of Allāh be upon him) came to a dumping ground of some people and urinated on it while standing. (3)

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(1) Sound due to corroborating evidence, except for his saying: "for most whisperings (from Satan) come from that," which is a stop (at the Companion). Al-Ḥasan—namely al-Baṣrī—did not explicitly state that he heard it from ʿAbdullāh ibn Mughaffal.
It is found in the Muṣannaf of ʿAbd al-Razzāq (978).
It was also narrated by Abū Dāwūd (27), al-Tirmidhī (21), and al-Nasāʾī 1/34 via Maʿmar, with this chain of transmission.
It is found in the Musnad of Aḥmad (20563) and the Ṣaḥīḥ of Ibn Ḥibbān (1255).
It has a supporting witness, longer than what is mentioned here, without his saying: "for most whisperings (from Satan) come from that," from a man who accompanied the Prophet (peace and blessings of Allāh be upon him), in Aḥmad's Musnad (17011), and its chain of transmission is sound.

(2) Al-Khaṭṭābī said in Maʿālim al-Sunan: Al-mustahamm is the place of bathing, and it is called mustahamm after al-ḥamīm, which is the hot water used for bathing. The prohibition applies only when the place is not firm solid ground, or when there is no channel through which the urine can pass and the water can flow, such that the bather might imagine that some of its drops or splashes touched him, thereby causing him whisperings (from Satan).
As for al-ṣārūj, al-Jawālīqī said: It is lime and its mixtures with which cisterns and bathhouses are coated. In Lisān (al-ʿArab): al-nūrah is from the stone that is burned and from which quicklime is made.

(3) Its chain of transmission is sound. Sharīk: he is Ibn ʿAbdillāh al-Nakhaʿī, the judge. Hushaym: he is Ibn Bashīr. Abū Wāʾil: his name is Shuqayq ibn Salamah.