The environmental and social benefits provided by green infrastructure make it an essential part of a city. Terms like sustainability and resilience are often attached to green space messaging, but what do these mean when planning and designing green infrastructure? Sustainability is about meeting our current needs without compromising the ability of future generations to meet theirs; it commonly focuses on avoiding resource depletion. Providing for current and future requires understanding (i.e. definition and quantification) of relevant green space services. Green space water schemes commonly involve a combination of mechanical and natural systems interacting with complex natural (plant based) systems. Specialist knowledge, skills and expertise are needed to develop long-life green systems. Design processes require data on system inputs and outputs. Currently there are very little data describing the green space outcomes or services side of the equation. This paper considers and reviews strategies to inform and balance this equation, including defining the green space services to be delivered, improving their consideration in planning stages across multi-disciplinary teams, strengthening their valuation, measuring and reporting of performance, and evaluating the effectiveness of supplementary water delivery.