Nearly three years of Israeli bombardment destroyed 90% of Gaza's water and sanitation infrastructure. All five of the territory's wastewater treatment plants are offline. The consequence: an estimated 45,000 cubic metres of raw sewage flows into the Mediterranean every day, with another 15,000 cubic metres seeping into groundwater. The pollution has now crossed the border in a way bombs cannot prevent. A microalgae bloom stretching 100 kilometres along the coast — fed by nitrogen and phosphorus from that untreated sewage — clogged filters at five of Israel's six main desalination plants. The plants were shut down for days and remain at reduced capacity. Israel's water authority is urging citizens to use water "judiciously" while farmers in the south have been ordered to halt irrigation, a move economists warn will push food prices higher. The mechanism is straightforward and was predictable. Gaza's coastal aquifer, which supplied 80% of the territory's pre-war water, is now contaminated by seawater and wastewater intrusion. Three Israeli-controlled pipelines were severed at the start of the war and only partially reopened. With no treatment capacity, everything flows downhill — into the sea. The Zalul Environmental Association, an Israeli NGO, stated plainly: "Pollution does not recognise political borders." Inside Gaza, the human cost is immediate and severe. Residents describe carrying water in jerry cans, queuing for hours, and choosing between drinking and handwashing. Acute diarrhoea is among the leading causes of illness. Raw sewage pools between tents in displacement camps. Rats have infested overcrowded areas, thriving on waste and rubble. Nada Majdalani of EcoPeace Middle East warned that hepatitis A cases are rising and a serious outbreak "would not necessarily remain within Gaza's borders." The rat infestation has already crossed the fence. Israeli communities near the Gaza border report unprecedented rodent swarms in homes and gardens — the same population explosion driven by the same raw sewage and refuse accumulation. Environmental and health consequences are operating on the same gradient as the sewage itself: downhill, indiscriminate, and accelerating. Both Zalul and EcoPeace have urged Cogat, the Israeli agency administering Gaza, to help restore Gaza's sewage system and allow wastewater treatment in Israeli-controlled areas. Cogat did not respond to a request for comment. The silence is telling: the agency responsible for the territory's civil administration has no public position on a crisis that is now degrading Israeli water security. The structural lesson is one environmental scientists have flagged for decades in shared-basin contexts. Destroy your neighbour's infrastructure and you destroy your own supply chain. Israel built the most advanced desalination system in the world — six plants supplying the majority of the country's drinking water — and rendered it vulnerable by eliminating the upstream treatment capacity that kept its marine intake clean. The algae bloom is not an act of nature. It is the predictable return on a policy of destruction.
