Water is an ever-increasing factor in the cost of oil and gas production. Globally, water produced by oil & gas wells easily exceeds total oil production, and in many cases water represents over 90% of the liquids brought to surface. Water handling - both produced water and water injected for reservoir pressure maintenance or enhanced recovery - can result in costly demands on surface facilities and operations. Water treatment systems are only part of the solution. A successful water management strategy is built on an understanding of the impact of water production on reservoir performance, production planning, surface facilities design, and water disposal or reuse options.