External water distribution system

• Minimum head ( pressure ) need to be provided to ensure adequate water pressure to raise water to the top of building . 
• Head can be provided by siting service reservoirs are suitable height above the building being served 
• Building higher than the head available need to provide pumping system 
• A water distribution system may be classified into three types :
• Gravity system 
• Direct pumped system 
• Gravity and pumped combination system 

The choce of type of distribution system depends on :
- Topography
-Distribution area
- Location
-Site elevation