The reference regulations is the Legislative decree dating back to April 3, 2006 n. 152, “Single text on waters” including the “Environmental regulations” published on the Official Gazette. n. 88 dating back to 14/04/2006.
As for rain waters, the Legislative decree 152/06, art. 113 “Rainfall water and washing water for exteriors” supplements what follows:
- As to prevent hydraulic and environmental risks, regions, after consulting the Ministry of the Environment and protection of the territory, govern any control on the run-off rain water discharges coming from separated sewages and cases which run-off rain water releases, through separated pipes, should undergo specific prescriptions, if not a possible authorisation.
- Regions govern cases where it can be required that rainfall and washing waters of any exterior are conveyed and duly treated in purging installations under specific conditions according to the enforced activities, where there is the run-off risk, from waterproof surfaces, of dangerous substances or substances affecting and compromising the water body quality goals.
- It is forbidden to release rain waters in groundwater.
The first regulation directly facing the issue is the Regional Law passed in Lombardy on May 27, 1985, n. 62 relating to the “civil settlement of public sewages and protection of underground water from pollution” where for the first time, “rainfall waters” are defined.
The regulations at present in force in the Region of Lombardy is the R.R. dating back to March 24, 2006, n. 4, governing the rainfall water disposal and run-off waters from exteriors, enforcing article 52, paragraph 1, letter a) of the Regional law, dating back to December 12, 2003 n. 26.
The regulation defines the “waters even from one or two rainfalls, temporarily separated as well by at least 96 hours from a similar event and defines rainfall waters, corresponding in the first part of the rain event, to a 5 mm rainfall, uniformly distributed on the entire draining surfaces, supported by the rain water collection network.
As to define capacities, the inflow coefficient account for 1 for waterproof surfaces.
In general terms, separation, interception and treatment of a consistent part of rain water coming from the flooring run-off under pollution risks, are defined as rainfall waters. Such water includes the highest loaded-polluted volume and therefore it is to be collected in suitable tanks and suitably treated before being moved to the allocated receptor.
The regions which already approved specific regulations are hereinafter reported:
- REGION OF LIGURIA: R.R. July 10, 2009 N. 4.
- REGION OF VALLE D'AOSTA: L.R. 24-08-1982 N. 59.
- REGION OF PIEMONTE: D.P.G.R. 13/R 4-12-2006
- REGION OF VENETO: D.G.R. n. 2884 dating back to September 29, 2009
- REGION OF FRIULI VENEZIA GIULIA: L.R. N. 16 dating back to 05-12-2008
- REGION OF EMILIA ROMAGNA: Resolution n. 2184 27-12-2007
- REGION OF TOSCANA: L.R. 28/2010 changing the regional regulation n. 20/2006
- REGION OF MARCHE: Resolution 07.02.2005 n. 157
- REGION OF UMBRIA: DGR July 9, 2007, n. 1171
- REGION OF ABRUZZO: L.R. 17/08
- REGION OF LAZIO: D.C.R. 27/09/07, n. 42
- REGION OF CAMPANIA: D.C.R. 6/07/2007, n. 1220
- REGION OF APULIA: D.C.E.A. n. 282 21/11/03
- REGION OF BASILICATA: L.R. 17/01/94, n. 3
- REGION OF CALABRIA: L.R. 03/10/97 N. 10
- REGION OF SARDINIA: L.R. N. 34 21-02-1997
- REGION OF SICILY: L.R. 27/86