One of the main duties of a water supply provider is to ensure that a safe and plentiful water supply is available to all segments of a community at a reasonable cost. This may mean seeking new water sources to satisfy demand. Identifying potential new sources and assessing their viability prior to development is a skilled technical task that requires several different factors to be assessed. These factors include:

• Volume of water required: This will depend on demand, which relates to the number and type of potential users. Will the new source be able to meet the demand of all users? Have future increases in demand and population growth been taken into consideration?
• Quality: Is the water from a safe and protected source? If not, what will be the level of treatment needed and how will this be achieved? What is the risk of pollution of the source?
• Seasonal variations: Is the new water source reliable, or is it vulnerable to seasonal variations in the availability of water? How will this be accommodated?
• Distance between source and users: How far must the water be transported? What is the sort of distribution system that will be needed? What are the engineering requirements for the system?
• Cost: Following on from all the above, what is the cost of developing the new source (both capital and continuing operating and maintenance costs) into the future?
• Environmental impact: What are the predicted environmental consequences of developing the water source? Will the benefits of the new supply outweigh any disadvantages?
• Sustainability: Can the water source be developed and used in such a way that it does not compromise the future ability to supply water? For example, the rate of abstraction from a spring should not exceed the rate of natural replenishment.

Answers to all of these questions and more, together with detailed surveys, assessments and analyses, will be required to identify possible new water sources. Mentioned in the list above is the possibility of pollution of the water source. There are many possible sources of pollution and these will be discussed in the next study session.