The government of Mayor Jaume Collboni is already preparing a new municipal ordinance for the use of so-called gray water. The objective of the Barcelona City Council is that the homes in newly built buildings, as well as those undergoing major renovations, have the appropriate infrastructure so that the toilet cisterns are supplied with the water that is normally lost through the sewers showers and bathtubs. The water that is diluted in bidets, sinks, sinks, dishwashers and washing machines is too dirty.
Municipal sources detail that the processing of the new ordinance begins now with the corresponding citizen participation process, that the objective of the municipal executive is for the new regulations to enter into force at the end of the year, at the beginning of 2025 at the latest . The accounts and calculations of the technicians reveal the reasons for the rush.
A household of four people generates around 200 liters of gray water every day. Each person spends, in terms of the cistern, an average of around 35 litres. Showers and bathtubs account for the majority of domestic drinking water consumption, and cisterns occupy the second position. The reuse systems reduce domestic potable water consumption by more or less 30%. We are talking about a potential saving every year in Barcelona of around 300,000 m3. This is an estimate based on the urban development of the city over the last five years.
Meanwhile, the works aimed at further exploiting the underground groundwater are still going at a good pace. This municipal investment is close to 14.4 million euros. Barcelona City Council is confident that the improvements will be ready next year. Who knows what emergency phase of the drought we will be in then.
In fact, many people have used gibberells all their lives to take advantage of the water that was lost through the drains of bidets, showers, bathtubs, sinks and sinks as much as possible, especially in places where the drought was always more that a circumstantial situation.
The first municipal ordinance of this kind is that of Sant Cugat del Vallès, in operation since 2002. Experts also highlight the ordinance for the efficient management and use of water in Madrid from 2006. In addition, after the 2010, other texts follow in municipalities of Andalusia, Galicia and Murcia. The Spanish Association of Water Treatment and Control Companies already published in 2011 a technical guide on the use of gray water for administrations, professionals, users…
The new Barcelona ordinance is part of the city’s Alternative Water Resources Plan and the 2030 climate emergency action plan, the main objective of which is to turn the Catalan capital into a city better prepared against climate crises . The regulations in process will affect all new construction buildings and major renovations of more than 16 homes or that have a consumption of more than 500 m3 each year in showers and bathtubs.
Previous analyzes indicate that in these cases the investment in this system is profitable. These buildings will only have to incorporate a small treatment plant where the gray water will be treated so that it can be reused in the toilet cisterns. Families will be able to save, in this way, nearly 100 euros each year.
These obligations have been in effect for a couple of years in the Gràcia district and in the 22@ by virtue of a modification of the General Metropolitan Plan. In addition, the municipal public promotion of 54 homes in the Besòs neighborhood where the City Council presented this initiative also makes use of gray water. Two more municipal promotions still under construction will also be added.
The biggest drawback of this system is that, if you spend a few days away from home without pulling the chain, when you come back you can smell a certain stench. However, the technical guide on the use of gray water says that it is enough to throw a disinfectant tablet in the cistern before you go on holiday and, when you return, stretch it four times.
