Water is of three kinds: (1) pure and purifying (ṭāhir ṭuhūr)—that which remains on its original characteristics; and of that is what drips from the grapevine.
تحفة الملوكZayn al-Dīn al-Rāzīكتاب الطهارة — تمهيد
Book of Purification — Preface
Water altered by contact with something pure (ṭāhir) is not deemed “changed” when the pure substance does not predominate over it in [respect of] parts.
And no new legal name is applied to it.
وطاهر فقط: وهو كلّ ماء أزيل به حدثٌ، أو أقيمت به قربةٌ.
Merely pure (ṭāhir) [not purifying] is every water by which a minor impurity (ḥadath) is removed, or an act of devotion (qurba) is performed.
ونجس: وهو ماء قليلٌ وقعت فيه نجاسةٌ وإن لم تغيره، وكثيرٌ وقعت فيه نجاسةٌ غَيَّرت أحدَ أوصافه، جارياً كان أو واقفاً.
Impure (najis) water is a small quantity into which impurity has fallen even if it does not change it, and a large quantity into which impurity has fallen that changes any one of its attributes—whether flowing or still.
والكثير: عشر في عشر بذراع الكرباس في عمق لا تظهر الأرض بالغرف.
The “large” quantity is ten by ten [cubits] in the forearm measure of Karbās, in depth such that the bottom is not visible when scooping.
والقليل: ما دونه.
The “small” quantity is less than that.
والجاري: ما يذهب بتبنةٍ.
Flowing [water] is that which carries away chaff.
والواقف: ما دونه.
Still [water] is less than that [sc. than flowing].
والنجاسة: كلّ خارج من السبيلين من الإنسان وغيره، إلا خرْء الحمام والعصفور.
Impurity (najāsa) is everything that exits the two passages of the human and otherwise, except the droppings of the dove and the sparrow.
والدم والقيح والصديد إذا سال إلى محلّ الطهارة في الجملة: يعني في الاغتسال والوضوء.
Blood, pus, and matter—when they flow to a place of purification in general, meaning in ghusl and wuḍūʾ [they are impure in that respect].
والخمر.
And wine [is najis].
والقيء ملء الفم.
And vomit of a mouthful.
وخرء ما لا يؤكل لحمه من الطير ينجس الماء، لا الثوب حتى يفحش.
The droppings of a bird whose flesh is not eaten render water impure, not clothing until it becomes excessive.
وخرء الفأرة وبوله معفوٌ عنه في الطعام والثوب، لا في الماء.
Mouse droppings and its urine are overlooked in food and clothing, not in water.
ودم البقِ والبراغيثِ والسمكِ عفوٌ.
Blood of lice, fleas, and fish is overlooked.
وشعر الميتة، وكلّ جزءٍ منها لا حياةَ فيه طاهر.
Hair of a dead animal (mayta) and every part of it in which there is no life is pure.
وشعر الخنزير وسائر أجزائه نجس، ورخِصَ الخرز بشعره.
Pig hair and all its parts are impure; beads (khurz) are permitted with its hair.
وعظم الفيل طاهر.
Elephant bone is pure.
وكلّ إهابٍ دبغ طَهر، إلا جلدَ الخنزير والآدمي.
Every hide that is tanned is purified, except pigskin and human skin.
[أحكام الآسار] وسؤر الآدمي طاهر إلا حال شربه الخمر.
[Rules of traces (āthār)] Human residual wetness (suʾr) is pure except in the state of his drinking wine.
وسؤر الفرس وما يؤكل لحمه طاهر.
Residual wetness of the horse and what may be eaten of its flesh is pure.
وسؤر الخنزير والكلب وسباع البهائم نجس.
Residual wetness of the pig, the dog, and predatory land animals is impure.
وسؤر الهرة، والدجاجة المخلاّة، والإبل والبقر الجلاّلة، والحيّة والعقرب والفأرة، وسباع الطير مكروه.
Residual wetness of the cat, the unconfined hen, camels and cattle that eat filth (jallāla), the snake, scorpion, mouse, and birds of prey is disliked (makrūh).
وسؤر البغل والحمار طاهرٌ مشكوكٌ في طهوريتِه، فإن لم يجد ماءً غيرَه، توضّأ به وتيمَّم.
Residual wetness of the mule and donkey is pure; purifying quality is doubted. If he finds no other water, he performs wuḍūʾ with it and does tayammum.