This document discusses water quality and sources. It defines safe and wholesome water as being free from pathogens, harmful chemicals, odor, and color, and able to be used for domestic purposes. It notes the physical demand for water is 2 liters per person per day and domestic usage in urban areas is 150-200 liters per person per day while rural is 40-60 liters. The main sources of water are listed as rain, surface water from reservoirs and rivers, and ground water from shallow and deep wells with sanitary wells being the most ideal.

1. ENVIRONMENT AND SANITATION
(WATER)
RAM KUMAR DHAMALA
HA, Government of Nepal
Lead Trainer,TITI/CTEVT
Skill Test Assessor, NSTB
ram.dhamala@gmail.com

2. WATER
SAFE AND WHOLESOME WATER
 Free from any pathogenic agent.
 Free from harmful chemical substance.
 Free from odor and color.
 Usable for domestic purpose.
Water is said to be CONTAMINATED OR
POLLUTED if it does not fulfill above criteria.

3. WATER
 PHYSICAL DEMAND : 2 Lit. water / head/ day
 FOR DOMESTIC PURPOSE :
 Urban : 150-200 L. / head /day
 Rural : 40-60 L / head / day

4. WATER
 SOURCE OF WATER
1. RAIN : Purest and softest form of water in nature.
2. SURFACE WATER : a. Impounding Reservoir
b. Rivers and Streams
( Main source of drinking water for Ktm valley )
3. Ground Water : Cheapest Source and Popular in Terai region.
A. Shallow wells : Taps water from above 1st impervious layer .
B. Deep wells : Taps water from Below 1st impervious layer .

5. WATER
 Most Ideal well : Sanitary Well
 Should be Located at least 50 feet ( 15 m) a way from
source of contamination.
 Should not be Located more than 100 m a way from residential area.

6. WATER
 Most Ideal well : Sanitary Well
 Should be Located at least 50 feet ( 15 m) a way from
source of contamination.
 Should not be Located more than 100 m a way from residential area.
 Guinea worm disease : Public health problem where STEP WELL is used.