Kathmandu valley has always been centre of development in  Nepal be it during Lichchhavi period or present Republic period. It has not just developed temples and other architectures but also developed sustainable water supply system for its citizens in form of stone spouts. A source that has been serving the kathmanduties from 2000 year continuously 365 days 24 hour and 7 days a week with sample quality.

Stone Spouts are Beautifully carved stone elements, in the shape of a crocodile head (considered as a holy water animal - the carrier of the Goddess Ganga) or serpent head, installed in the front or side walls of sunken and stepped platforms for the purpose of channelling water for human use. Stone spouts are the unique outcome of excellence of ancient engineering and architecture. Stone and metal crafts evolved with the stone spouts as new construction methods and designs were employed. Many of the fonts are shaped like the head of a snake, with the water pouring out of the mouth, honouring the connection between snakes and rain. Images of crocodile mouths were used in the same way. In ancient  Nepal, people used to worship the source of water and managed them according to the situations and circumstances.

"Water is linked with religion. Offering adequate water to thirsty people is regarded as a virtue and taking money to offer the water is a sin," says Dr. Safalya Amatya, a Nepali archeologist. Construction of stone starts from Kirat dynasty,the knowledge and skills were continued and enhanced in Lichchhavi Period and further extended during Malla Period.

In Patan  the oldest stone spout was recorded to be build in 570 A.D. i.e. Manga Hiti (Manga Stone spout) and the youngest is Alko Hiti build in 1415 A.D. Other Famous old hities (Stone spout) of patan are Nuga Hiti (Sundhara), Thapaa Hiti, Taapaa Hiti, Chyasal Hiti, Tyaga Hiti, Konti Hiti, Natwaa Hiti, Wasa Hiti, Sauga Hiti and many more.

There are total 60 stone spouts in patan but most of them are in verge of collapse (NGOFUWS, 2006).The supply of water to the hitis depends both on ground and surface water. Most stone spouts receive water from either an individual spring or nearby aquifer. A single aquifer may supply water to one or many stone spouts. The aquifers are largely dependent on rainwater for recharge and maintenance of the groundwater table. So, nature based supply system were: 24 hours running in same rate throughout the year, Cold water, Carry medicinal value, Use of calcium carbonate stone, Underground channeling, Natural treatment method are the speciality of the stone spouts  at the mean time in winter season, discharge nearly three million lt of water discharge per day and In rainy season, discharge nearly eight million lt of water per day. (Source: NGO forum).

However  Stone spouts which is a symbol of Nepalese engineering excellence along with social, historical and cultural monument is degrading and disappearing, unless we start to conserve it from now, we will lose it forever.