Criteria on the attribution of costs to services with public goods characteristics, such as flood control, should be harmonised according to transparent criteria. Higher, cost-reflective prices for irrigation water would also go a long way in reducing groundwater pollution through the use of chemicals. Numerous studies have shown that more efficient water use reduces agricultural pollution (e.g. Calatrava and Garrido, 2010). A recent government report (MMA, 2007a) shows that access to these data needs to be improved.