Larger irrigation systems normally have a storage tank and pump. This allows for larger sprinklers and a greater number of sprinklers to be operated at the same time.
A tank should be sized to have a usable amount of water to enable the watering system to apply one night's application, without stopping half way through the irrigation cycle to allow the tank to refill. The usable amount of water is reduced by the amount of water that flows into the tank when the system is running. Please note : the usable amount of water is not the same as the storage capacity of a tank as you can't generally totally empty the tank and totally fill a tank.
Pumps can either be located in the tank or in a kiosk / shed. They can be a fixed speed pump or a variable speed pump. If a fixed speed pump is used a pressure relief valve should be fitted.