Water Crisis: The Best Water Systems against Pollution and Water Scarcity

In every major metropolis there are invisible infrastructures upon which the quality of life of millions of people depends. These are the water networks, the purification, drainage, and treatment plants, the tunnels that collect wastewater and return it purified.

Their story reaches back to the dawn of time, from the sewage management systems of the Ancient Romans to the drainage canals along the Thames in nineteenth-century London. Yet today, with the rise in water pollution problems and increasingly extreme weather events, they are more than ever at the heart of urban and climate strategies. Because without efficient water supply systems there can be no resilience, without wastewater filtration there can be no public health, and without water infrastructures there can be no future.

According to the UN, by 2030 more than 2.4 billion people will be living in cities facing chronic problems of water supply or disposal. These figures portray a global water crisis redefining the priorities of governments and major investors: building water networks to free cities from the risk of an endless emergency.

In Buenos Aires, along the course of the Riachuelo River, the water is breathing again. For over a century, it was among the most polluted rivers in South America, filled with industrial waste, urban discharges and refuse.

Today, thanks to one of the largest wastewater treatment and sewage management projects ever carried out in Latin America, the river is changing its face. The project, built by the Webuild Group and its subsidiary Fisia Italimpianti, involved the construction of a system of underground tunnels, collectors and wastewater treatment plants capable of returning millions of cubic metres of purified water to the Río de la Plata every day.

The Riachuelo Project therefore represents the rebirth of a metropolis that for decades had neglected its river pollution. A rebirth not only environmental, but also urban, economic and social.

There was a time when the sea of Faliro, on the outskirts of Athens, was synonymous with decay and water pollution problems.

Today, the beaches are clean once more thanks to the Psittalia water treatment plant, one of the largest in the Mediterranean. The complex, built on an artificial island, enables wastewater treatment for over 4 million inhabitants: it is a silent machine that has given new oxygen to the Saronic Gulf.

The initiative has turned an environmental problem into an opportunity for urban and tourism development, making it a model replicated in other coastal cities such as Barcelona and Tel Aviv, where water infrastructures have become architectures of regeneration.

In the Peruvian capital, the water crisis is the opposite yet just as dramatic: not an excess of water, but a lack of it. In a context where rainfall is increasingly scarce, the construction of major water collection and water distribution systems has become a national priority.

The Huachipa–La Atarjea system, with its pipelines and pumping stations, guarantees potable water supplies to more than three million people, while a parallel treatment plant is transforming wastewater into a resource for agriculture.

In this way, Lima demonstrates that even water scarcity can be tackled through engineering.

Mexico City is one of the largest metropolises in the world. Its metropolitan area, which also includes 59 municipalities outside the city centre, covers 7,800 square kilometres and has a population exceeding 20 million inhabitants.

Ensuring water supplies for such a vast population is therefore a unique challenge. Hence the decision to build, in the Hidalgo area, the mega-project Atotonilco Wastewater Treatment Plant, a massive purification facility capable of treating about 1.99 million cubic metres of water per day.

This water system has radically changed wastewater treatment in the Valley of Mexico and paved the way for a new era of hydraulic infrastructures focused on efficiency and sustainability.

Across Europe, water problems have also become central to public debate and community policy. The new directives of the European Union, enacted in 2024, require member states to reduce water network losses by 20% and to reuse at least 30% of purified water by 2030.

In Italy, over 40% of drinking water is lost through obsolete water networks. The response is a wave of major investments involving public authorities, operators and builders. From the Tiber collectors in Rome to urban drainage projects in Milan and Naples, a new chapter is opening: maintenance becomes innovation, and water infrastructures regain their strategic role alongside motorways and railways.