When rain falls on concrete: Naples and Italy’s vanishing urban soil
Published on 16 October 2026 at 03:48 GMT
By Valeria Russo
How much rain does it take for a city to realise it has left the ground nowhere to absorb it? In Naples, the answer begins with what we have built, paved and tarmacked, often treating open land as space waiting for another use. The problem becomes visible when water struggles to find a way through. Its origins lie much earlier, in planning decisions, car parks and the conversion of open spaces. Understanding it means reading national maps alongside the city’s streets, without blaming climate change for every flood.
During the long dry spells of summer, rain can seem to have forgotten Naples. Then a downpour, like those of recent autumn days, changes the city within minutes. Water rises to the rims of street drains. Trickles become streams across the tarmac, running from the streets of the Vomero hill towards the centre. Reports of fallen trees and masonry coming loose from rain-soaked balconies add to the picture. Residents know this abrupt transformation well. Explaining it requires a distinction between the rain that falls and the city’s ability to drain it.
In their 2025 land take report, covering 2024, ISPRA, Italy’s environmental research institute, and the national environmental protection network recorded almost 84 square kilometres of new artificial ground cover across Italy. After restored land is deducted, the net loss exceeds 78 square kilometres, the highest figure in a decade. In Campania, 10.61% of the land is under artificial cover, placing the region behind Lombardy and Veneto.
These figures describe changes to the ground, not rainfall. The report’s municipal database brings the issue closer to home: in 2024, Naples had 7,546.5 hectares under artificial cover, representing 63.68% of the municipal area used in the calculation. The net increase between 2023 and 2024 was 13.37 hectares. Almost two-thirds of the territory is therefore classified as consumed land. This is the municipality of Naples, rather than the wider metropolitan area.
That percentage needs careful handling. In ISPRA’s terminology, “land take” and “soil sealing” are not interchangeable. Land take includes both permanent and reversible artificial cover; sealing refers to changes that prevent or reduce water infiltration. The 63.68% figure is therefore not an exact measure of completely sealed ground. Blurring the distinction would produce a more dramatic story and a less reliable diagnosis.
Satellite maps reveal differences that a city-wide average conceals. Establishing how much water a particular planting bed can absorb, however, requires information about its soil and local conditions.
Piazza Garibaldi and the Villa Comunale offer a useful comparison. One is the city’s railway gateway, designed around movement, transport and public space; the other is a historic garden along the Riviera di Chiaia. Trees alone cannot tell us how either place handles water.
Piazza Garibaldi is hardly a treeless desert. In November 2019, the council announced the opening of its redesigned northern section, with 130 trees, an agora, play areas and other amenities. That records a design decision made at the time. It neither confirms that every tree survives today nor measures the square’s overall permeability.
How much room do roots and rainwater have between the paved surfaces? A tree can provide shade while standing in a very small patch of permeable ground. Counting canopies cannot replace checking where water can soak in and whether runoff can reach those areas.
The council’s description of the Villa Comunale puts its enclosed area at 110,000 square metres, or 11 hectares, between Piazza della Repubblica and Piazza Vittoria. That is the size of the park, including paths and buildings, rather than a guarantee of 11 permeable hectares.
Planting beds and vegetation offer opportunities for infiltration that sealed surfaces do not. But even a garden has limits. Compaction, soil type, saturation and paved paths can all reduce absorption. The comparison raises questions about soil quality; without measurements, it cannot establish which site performs better during a storm. Nor can a waterfront park simply offset soil lost elsewhere. Each intervention must be assessed within its own drainage catchment.
Naples’ Sustainable Energy and Climate Action Plan, known as PAESC and approved by the city council in July 2025, examines the relationship between ground cover and flooding. It estimates urban soils’ infiltration capacity using mapping updated in November 2024. A separate map, Figure 43, models surface water accumulation under a heavy-rainfall scenario.
The document makes an important limitation explicit: the model does not directly account for the sewer network’s contribution, assuming that it becomes saturated during extreme events. The simulation can inform planning. It cannot, by itself, explain every flood that occurs.
That requires evidence about rainfall intensity and duration, slopes, runoff routes, pipe capacity and the condition of street drains. Climate change can alter the likelihood and intensity of certain events, but attributing an individual flood requires dedicated analysis. As the IPCC explains, whether heavy rainfall leads to flooding depends on several factors, including land use and water management.
PAESC includes an action on removing paving, restoring permeability and developing green and blue infrastructure. It proposes linking planted spaces and restoring degraded soils. Yet the action remains a programme of intent, with no overall estimate of the funding required. Its inclusion in a plan does not mean work has been completed.
Public scrutiny should start with practical questions: how many square metres are being freed from paving, where, with what funding and with what provision for maintenance? Publishing those figures would allow residents to judge measurable progress, beyond photographs of refurbished spaces and opening ceremonies.
Naples also needs more greenery to cope with heat. During the sweltering summer of 2026, the need for relief became a public concern: on 29 July, the council presented a map of cooling refuges and drinking fountains. More trees, planting beds and shaded routes are needed, including in neighbourhoods where finding shelter means leaving the places people use every day.
Tree canopies provide shade, while vegetation cools its surroundings through evapotranspiration. In a city choked by traffic fumes, giving Naples breathing space also means improving the conditions in which people live. Plants release oxygen and can help capture some pollutants. Those benefits belong alongside measures to cut vehicle emissions. Species, location and maintenance matter as much as tree numbers. Greenery should be planned for public health as well as appearance.
Rain and heat expose two consequences of the same decision: how much room we leave for living soil. In Naples, removing paving and expanding greenery can improve both water management and everyday life. Before the next storm or the next punishing summer, the question is how much ground the city is prepared to give back.
Written by a human author, edited with AI assistance.
Further information:
* ISPRA and the National Environmental Protection System, 2025 land take report covering 2024, with national and regional figures.
* Comune di Napoli, official description and recorded area of the Villa Comunale. https://www.comune.napoli.it/vivere-il-comune/luoghi/villa-comunale/
