Shaykh Muḥammad ibn Ṣāliḥ al-ʿUthaymīn said [concerning the ones who divide water into three types]:
ṭahūr [amenable for wuḍūʿ],
ṭāhir [clean in and of itself but not amenable to wuḍūʿ],
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...