The water work department that involve in the collection purification and distribution of portable water to the community or civils.

In Cameroon it is carry out by a company called CAMWATER they water to be purified can be collected from a river and chanel to the WWD by pipes under gravity.

Purification of water passes through 6 main stages as shown below.

1. SCREENING: the water from the source in bomp through a grid screen which remove large solid particle such as bottle, sticks etc.
2. SEDIMENTATION AND COAGULATION:                                                                 sedimentation:  water from the grid spring is chanel in large open tanks for sedimentation of solid particles like sand and gravel to occur.                  Coagulation: fine particles can be force to settle faster or coagulated faster by adding alum. This is because the alum makes the fine particles to cling together at such it became heavier and sink to the bottom.
3. FILTRATION: the water is them form in a filtration tank(send filter) to remove suspended particles. The surface of the sand is what cover hence the water is expose to sun light which destroys some of the surface bacteria. Also the growth of algae on top of a layer of sand from slime which act as a filter for bacteria. Protozoans on the slime also feet or eat up some the bacteria. NB: the filter bed with a proper growth of slime called a ripe bed.
4. CHLORINATION: after filtration the water is passed into a chlorination tank, where calculated amount of chlorine is added Into water so as to kill the remaining germs or bacterial.NB: the presence of chlorine should not be eviden in water either by taste or smell. Thus only about OS part of chlorine only added after filtration on because it kill the protozoans on the slime bed manages to cross the filtration on level. Also chlorine remove odour and taste due to organic matter.
5. SERVICE RESERVOIRS: after chlorination, water is tasted for it purification into large scale reservoirs. Services reservoirs are situated on hills near town or cities or raised over houses if the land is flat. This is due to ensure another head pressure, so that water should be distributed by simple gravity to houses. Also the concrete tanks are covered to avoid real contamination from other animals and germs to fall inside.
6. DISTRIBUTION: water from the main service tank is chanel to domestic tanks through pipe that the service tanks until water reaches the home or house for consumption.