Sanitation plan per river sub-basin (Pash)

Map of river basins and sub-basins

Water falling from the sky flows from top to bottom, from upstream to downstream. To water, municipal, provincial, regional and national boundaries are obviously utterly nonexistant. Water flows in sub-basins that merge in river basins.

In Wallonia, there are four basins – Scheldt, Meuse, Rhine, Seine (this one being very small; its tributary is the Oise river) – and fifteen sub-basins. The boundaries of those basins and sub-basins were adopted by the Walloon Government on 13th September 2001.

The fifteen sub-basins lead to fifteen PASH (Plan d'Assainissement par Sous-bassins Hydrographyique, literally sanitation plan per river sub-basin), thereby replacing the former PCGE (Plan Communal Général d'Egouttage, literally general municipal plan for the sewerage).

The PASHs have the advantage of allowing a greater coherence in the regional conception of the water treatment and clarifying everyone's belonging to a sanitation area.

There are indeed three types of sanitation areas:

1. The areas of community sanitation regime (previously drainable areas). These are areas where sewers are or will be linked to community water treatment plants;

2. The areas of autonomous sanitation regime (previously individual treatment areas). These are areas where inhabitants must take care of the treatment of wastewater themselves, individually or in small communities;

3. The transitory areas that have not been classified yet for various reasons, but which will be assigned to one of the other two regimes.

Map of river basins and sub-basins


Waste Water Plans