some benefits are likely to tail away as there tends to be diminishing returns from further investments in improving quality of water related services benefits are more likely to materialise if investments are appropriately sequenced thereby lowering costs and ensuring that collected wastewater is properly treated the accelerated access scenario indicates that globally an average of usd billion would need to be invested each year between and to achieve the target in addition to what would be invested under the baseline scenario and an additional usd billion beyond the baseline would be needed annually between and to achieve the target