Shaykh Muḥammad ibn Ṣāliḥ al-ʿUthaymīn said [concerning the ones who divide water into three types]:

1. ṭahūr [amenable for wuḍūʿ],
2. ṭāhir [clean in and of itself but not amenable to wuḍūʿ],
3. and najis [not amenable to wuḍūʿ],

The correct opinion [in this matter] is that water is divided into just two types: ṭahūr and najis.

If water is changed [in taste, colour, or smell] by something that is considered najis, then that water is najis. Water that is unchanged by najis is ṭahūr. As for the [third] division of ṭāhir, it does not exist in the sharīʿah. This is also the opinion taken by Shaykh al-Islām Ibn Taymiyyah. The evidence of this is the lack of evidence. For if the class [of water] termed ṭāhir was present in the sharīʿah, it would have been a widely known, well understood division clarified and espoused in aḥādīth. This is because the [presence of such a class] is not a trivial or meaningless matter; it can determine whether or not an individual purifies himself with water or has to make tayammum. Thus, people would have a dire need to know [of this class of water] just as they have a requirement to be aware of that which nullifies their wuḍūʾ and other similar matters that would have been related to us if confirmed.

Source: al-Sharḥ al-Mumtiʿ:54
Translated by: Riyāḍ al-Kanadī