This section is from the book "The Sushruta Samhita", by Kaviraj Kunja Lal Bhishagratna. Also available from Amazon: The Sushruta Samhita.
A broad piece of clean and white linen should be hung out in the open air, (with a stone placed across the middle to clip its centre of gravity). The rain water thus collected should be kept in a vessel. As an alternative, rain water flowing from the waterspouts of a house should be collected in a clean receptacle, and subsequently poured into a golden, silver or an earthen vessel. The water thus collected can be taken at all times, and may be substituted by any other terrestrial water in the event of its not being available at the time.
Terrestrial water is generally marked by a predominance of the specific properties of the sky, and admits of being grouped under seven sub-heads such as, well-water, river-water, lake-water, tank-water, fountain water, spring (Artesian) water, and Chunti (well unprovided with masonry steps) water. Atmospheric or spring water should be used for their high efficacy during the rains (Varsha). All kinds of water may be used in Sharat on account of their clearness. Lake or tank water should be used in Hemanta; well and fountain water, in spring * (Vasanta) and summer; and Chunti water, as well as all water not of recent origin, nor due to an excessive down-pour or inundation, should be used during Pravrit.
He falls an easy victim to internal and external diseases (cutaneous affections), etc., who drinks of or bathes in a pool of water, which is full of poisonous worms, or is saturated with urine or fecal matter, or is defiled with germs of vermin or decomposed animal organisms, or is covered over with the growths of aquatic plants, or is strewn over with withered and decomposed leaves, or which in any way is rendered poisonous and contaminated, as well as he, who drinks and bathes in the freshly collected water of a pool or a reservoir during the rains.
* The "rains" in the present passage should be interpreted to mean the end of the rainy season or the month of Ashvina, and not the month of Bhadra, as its use is specially forbidden in that month.
A sheet of water, which is entirely covered over with the growths of aquatic plants such as, moss, zoophytes, water weeds, lotus leaves, etc., or which looks turbid owing to oozy mire, or is not exposed to the currents of fresh air, nor illumined by the sun or the moon, and is possessed of a definite smell, colour, and taste, should be regarded as contaminated or defiled (Vyapannam). Water may be affected with regard to the six categories of touch, sight, taste, smell, potency, and chemical transformation or re-action (lit : digestion), Roughness, sliminess, warmth, and the production of a shivering sensation (lit : tooth-edge) are the tactual defects (Sparsha-Dosha) of defiled water, whereas a varied colour, and the presence of mire, sand, and shreds of moss are the defects, which mark its look or appearance (Rupa-Dosha). A distinct taste marks the water, which is affected as regards its taste (Rasa-Dosha), while an unpleasant smell is the characteristic of the water, which is affected as regards its smell (Gandha-Dosha). The water, which being taken gives rise to thirst and to a sense of heaviness of the limbs, colic, and a flueut coryza, is said to be affected or vitiated in its potency (Virya-Dosha) , whereas that, which takes a long time to be digested, or is retained in the stomach for an inordinate length of time, is said to be affected as regards digestion or chemical transformation (Vipaka-Dosha). Atmospheric water is free from the abovesaid defects. The defiled or contaminated water should be purified by boiling it, or by heating it in the sun, or by immersing a red-hot iron, or hot sands or stones in the same, and its smell should be removed by perfuming it with the Nageshvara, Champaka, Utpala, or Patala flowers, etc.
Water should be drunk perfumed in a golden, silver, copper or an earthen goblet, or in a bowl made of bell metal or of precious stones. Contaminated water, as well as rain water accumulated in an improper season, should never be used for drinking purposes, inasmuch as it tends to derange the fundamental humours of the body, and is positively injurious to the human system. The man, who drinks, or bathes in, any contaminated water without previously purifying it as before directed, incurs the risk of being speedily affected with oedema, jaundice, cutaneous affections, indigestion, dyspnoea, cough, catarrh, colic pains, abdominal glands, ascites or any other dreadful disease.
There are seven modes of purifying water such as, by immersing the Kataka fruits, the gems known as the Gomedha, the roots of lotus plants, or of aquatic mosses, a piece of linen, or a pearl, or a crystal in a pitcher or vessel containing it. The bottoms of a water pitcher are made of five different shapes such as, the Phalakam (rectangular wooden stool), the Tryashtakam (octagonal wooden tripod), the Manju Valayam (ring made of the blades of Manju grass), the Udaka-Manchika (wooden scaffold for a pitcher) and the Shiky (pendent bracket). There are seven ways of cooling water, such as by exposing a water pitcher to currents of air, immersing a water pitcher (tied round with a piece of wet cloth) neck-deep in a vessel full of water, churning it with a stick, by fanning, or siphoning it by means of a piece of linen, or by burying a water pitcher underneath a bed of sand, or by keeping it suspended in a pendent bracket.
The water, which is devoid of all smell or taste, and is pure, cool, limpid, transparent, refrigerent and pleasant, should be regarded as possessed of all the commendable traits. The water of rivers, (which drain the Jangala countries) and flow into the western sea, is light, and therefore wholesome. The water of rivers, which traverse the marshy (Anupa) countries and empty themselves into the eastern sea, is heavy and therefore not commended to be used. The water of rivers, which run into the southern sea, is neither too heavy nor too light owing to the fact of its traversing countries which have a Sadharana character.
 
Continue to: