This document discusses the cold water supply for a plumbing unit. It begins with an overview of the hydrology cycle, including the processes of evaporation, transpiration, condensation, precipitation, and runoff. It then discusses sources of water supply such as lakes, streams, rivers, and reservoirs for surface water and wells and springs for underground water. The document also covers examining water samples using acid and alkali litmus paper and defines water hardness in terms of calcium and magnesium ion content, and methods for softening hard water.

1. CB 205
PLUMBING SERVICES
UNIT 1
COLD WATER SUPPLY
Prepared:
Mrs. Izyan Wahida Binti Zainuddin
Civil Engineering Department
Polytechnic Kuching Sarawak

2. RAIN / HYDROLOGY CYCLE

3. PROCESS IN
HYDROLOGY CYCLE
evaporation transpiration condensation
precipitation runoff

4. evaporation
• Change of state in a substance from liquid to a gas.
transpiration
• Evaporation of water from plants
condensation
• Process whereby vapor in the atmosphere is
returned to its original liquid state.
Precipitation
• Tiny condensation particles grow too large and fall to
earth.
Run off
• Occurs when there is excessive precipitation and the
ground is saturated.

5. SOURCE OF WATER SUPPLY
-Lakes
-Streams
-Rivers
-Reservoirs
SURFACE
-Wells
-Springs
UNDERGROUND

6. WATER SAMPLE EXAMINATION
Acid – litmus paper turns red
•A substance containing hydrogen which
can be replaced by other elements.
Alkali – litmus paper turns blue
•A substance which will neutralize acid
by accepting its hydrogen ion

7. WATER HARDENESS
• Hardeness means it is difficult to obtain with a
soap
• Hard water is water that has high mineral
content which are high concentrations of Ca2+
and Mg2+ ions.
• Not harmful to one’s health but can pose
serious problem is industrial settings.
• Lead galvanic corrosion in plumbing system

8. WATER SOFTNESS
• Reduction of concentration of calcium,
magnesium and other ions in hard water.
• Taste salty
• Reverse osmosis, distillation and deionization.