However, countries with stronger customary traditions have tended to limit the abstraction of groundwater to levels non-detrimental to their neighbours, while those who have increasingly relied on Roman law tradition have usually not placed any restrictions on the "use and abuse" of groundwater by each landowner, be it in the end detrimental to his neighbours. In all countries, however, when public water supplies rely on groundwater, public control of the water and of the land above has gradually developed.