As far as water protection is concerned, a distinction is usually made between the protection of the qualitative aspect, i.e. the chemical state of water bodies from pollutant inputs, and the protection of the quantitative aspect, in order to ensure proper water management and to avoid excessive use that could have effects of unsustainable depletion of water resources and damage to the hydrogeological structure of the territory.

To this end, the national territory is divided into the hydrographic districts provided for by art. 64 of Legislative Decree 152/2006.

For each of them is established a basin authority, which has the task of preparing the District Basin Plan, which has the value of territorial plan of the sector and is the knowledge, regulatory and technical-operational tool by which actions are planned and programmed and the rules of use aimed at the conservation, defense and enhancement of the soil and the proper use of water.

It is classified as an act of guidance and coordination with a mixed legal nature and indefinite validity.

The basin plan, before its approval, is subject to a strategic environmental assessment (VAS) at State level, and is implemented through triennial programs of intervention.

The quantitative water protection policy, pursuant to art. 95 D.lgs 152/2006, is integrated with the qualitative one and therefore contributes to the achievement of the quality objectives of the water bodies according to their specific destination fixed in Title II of Part Three of the Consolidated Bill for the Environment.

A central tool is the water balance planning provided for in the Water Protection Plan, as per art. 121 of Legislative Decree nr 152/2006.

The drafting of the Plan, which constitutes an excerpt from the sectoral plan of the Basin Plan, is delegated to the Regions, in agreement with the Basin Authorities.

Underpinning the Protection Plan is knowledge of the natural quantitative aspects that characterize the water bodies, in order to achieve the two main objectives of the Plan itself:

– the maintenance or rebalancing of the water balance between availability and withdrawals, which is essential to define the compatible uses of water resources in order to safeguard them in the future;

– the estimation of the quality characteristics of the water bodies through the intensification of the monitoring and the consequent definition of the interventions for the achievement of the quality objectives.

The measures aimed at ensuring the balance of the water balance must be applied, above all, when granting diversion permits, governed by Royal Decree nr. 1775 of 1933, to which extensive and appropriate amendments have been made over time, precisely with regard to water saving and recycling, by art. 96 of Legislative Decree 152/2006.