Because there was always a systematic water supply system (Hiti) in the Kathmandu Valley, the people of Kathmandu Valley never had to relocate their locality. Whereas, many other civilizations have to move to other places due to the improper water supply.
Through cannel, water was supplied to ponds, water tanks and then using terracotta tunnels, it used to get supplied to the local residents via stone spouts. And this system was already developed during the Kirat reign in the Kathmandu Valley. (Parajuli, pg. 3)
It is said that in the 6th century CE, Kathmandu was the only city in the world that had mastered the technology to sustainably provide drinking water to its inhabitants deep in core residential areas. Free-flowing, safe drinking water was available in the city round the clock, throughout the year.
And it was only possible with the development of stone conduit along with Rajkulo, of course. Stone Conduit, locally named Lho hiti might be the initial picture of the stone spout. Because we can find such water conduits throughout the Kathmandu Valley, and they definitely are not made out of stones only.
Hiti (conduit) is a typical newari word, that means a blood-like liquid. But many people have defined it from different perspectives. Blood-like liquid doesn’t mean, in that stone spout, blood flows. However, it means, it flows water as important as our blood.
In the ancient time, it used to have its own importance. These conduits not only were the source of drinking water, but a holy place to make yourself pure. The people back then, used water from those conduits to do worshipping in the temples. Besides that, it used to be an open space to showcase the art of artisans. Even simple stone conduits, we can still witness, are filled with the carvings of strange creatures’ along with the god and goddesses.
Most of the spouts of the Hiti (conduit) have Makara, (crocodile), an aquatic animal through the mouth of which water flows. It is a carrier or vehicle of Ganga. The back and sides of the Hiti are replete with the artistic carving of many aquatic animals such as serpents; frogs and others. The mouths of some Hitis also have the heads of goats, fish, elephants and other creatures. These signify the symbolic meaning of cohabitation and the coexistence of human beings with animals.

According to the research of Ganesh Khaniya, the cut-throat competition in art and craft among the kings of the valley during the Malla period prompted the development of the exquisitely innovative design of Hiti making them legendary masterpieces. (Khaniya, pg. 38)
More than drinking, the people used that space of Hiti for worshipping and other important holy rituals. For drinking, they used to use the water from wells, as an alternative.
However, in the present context, this act of using conduit water seems impossible. Because most of them are now dry. Yet, the importance of these conduits has remained relatively high. Instead, these conduits have become a more important component for the study of art and history.
Just by a glance, an archaeologist could say how old is the conduit and if it has luckily some readable inscriptions, then, it’ll be the best resource to study history. Just from a simple inscription, we can find more about the place’s history and significance, not only the conduit. If not much, we could assume the social welfare of the past, when that conduit was made.
On top of that, the art dispersed in and around such conduits will further help to uncover more history about the locality. Thus, today, we can take the conduit as not only a conduit but practically a historical lab.
Of course, in the past, it might have been more lively, where men and women gather in the morning to start their Nityakarma in those stone conduits.
What is so fascinating about stone conduit?
Well, every corner of a conduit is as fascinating as exploring an artistic city. If you look carefully, then, you will see there won’t be just a conduit staging in front of you. There would be various other sculptures of gods and goddesses. There would be Jaladroni (a traditional water tank).

Generally, there would be an image of Umamaheshwara, Narayana, or Laxminarayan above the conduit and the icon of Bhagirath beneath it. Of course, the sculpting of them varies per conduit but however are they sculpted, they look too fine to be established on the conduit.
Besides these sculptures, there could be Shivalinga and a small chaitya nearby, clearly depicting the religious harmony of that time. Somewhere, the Purna Kalasha is also carved on either side of the conduit. It is rare but in the conduit near the Bhairavanath Temple of Bhaktapur, there are mini sculptures of Navagraha.

Conduits have been found in different places within the Kathmandu Valley. Besides Kathmandu Valley, there are very few places where you can encounter decorated stone conduits. You can notice that where there are Newa settlements, there are such stone conduits. And there is a strong belief in establishing such conduits.
Merit earning was one of the driving forces which encouraged high-profile royal dignitaries as well as commoners to contribute worth remembering deeds. Yaksha Malla, Jeetamitra Malla, Bhupatindra Malla and other Malla kings were pioneer contributors to many infrastructures such as Dhara, pond, Pati, temples etc. Bhaju Kasha, a brave royal adviser made Bhaju Pokhari for earning merit as well as
exhibiting his courage.
On the commoners’ front, a widow made Pulan Dhara in 1586 with the earning she made through weaving cotton thread. Gosain Hiti and Dhawbadhel Hiti were through community effort. They put the stone inscriptions mentioning the do’s and don’ts regarding their upkeeping and maintenance. (Khaniya, pg. 28)
Hence, Lho hiti (stone conduit) is one of the most beautiful legacies of Nepal which we need to protect.
References:
Khaniya, Ganesh: 2005, TRADITIONAL WATER MANAGEMENT PRACTICES: A CASE STUDY OF BHAKTAPUR CITY, Kathmandu, Jalsrot Vikas Sanstha (JVS)
Parajuli, Dr. Sandhya Khanal, 2020, काठमाडौं उपत्यकाका ऐतिहासिक राजकुलो; Central Department of NeHCA, Tribhuvan University, Kathmandu, Nepal