US Strikes on Iran’s Water Plants and Bridges and International Law

As thesecond part of the United States war on Iran enters its seventh consecutive day of strikes, the nature of the targets has shifted dramatically. Recent U.S. military actions have reportedly hit bridges, rail lines, power grids, and drinking water facilities in southern Iran near the Strait of Hormuz. With a previously declared cease-fire agreement now collapsed, this escalation raises profound and urgent questions about compliance with international humanitarian law.

The reported destruction of a drinking-water facility serving thousands of civilians is not merely a tactical escalation; it is a potential violation of the foundational rules of armed conflict. Under international law, the conduct of hostilities is governed by three core principles: distinction, proportionality, and precaution.

First, the principle of distinction requires parties to a conflict to distinguish at all times between civilian objects and military objectives. While bridges and power facilities can sometimes be considered "dual-use" infrastructure, water treatment and distribution plants are presumptively civilian objects. For a dual-use object to become a legitimate military target, it must make an effective contribution to military action, and its destruction must offer a definite military advantage. The burden of proof rests on the attacking force to demonstrate this, not on the defending state to prove the object’s civilian nature.

Second, and more critically, international law explicitly protects objects indispensable to the survival of the civilian population. Article 54 of Additional Protocol I to the Geneva Conventions prohibits attacking, destroying, or rendering useless objects such as drinking water installations and supplies. Although the United States is not a party to Additional Protocol I, this specific prohibition is widely recognized as a norm of customary international law, binding on all states regardless of treaty ratification. The destruction of a water facility on Iran’s southern coast, which reports indicate could impact tens of thousands of civilians, directly tests this absolute red line.

Third, the principle of proportionality prohibits attacks where the expected incidental harm to civilians would be excessive in relation to the concrete and direct military advantage anticipated. Even if the U.S. military argues that a bridge or a water plant supports Iranian logistical movements, the long-term humanitarian consequences of depriving a civilian population of clean water must be factored into the proportionality calculation. The collapse of water infrastructure often leads to secondary public health crises, which compounds the civilian harm far beyond the initial blast radius.

The U.S. military’s recent statements have made no specific mention of civilian infrastructure, focusing instead on the broader operational campaign. However, silence on the matter does not equate to legal compliance. In modern warfare, the normalization of striking dual-use or civilian infrastructure sets a dangerous precedent. If major military powers freely interpret "military advantage" to encompass the degradation of a nation’s basic life-sustaining systems, the entire framework of the laws of war risks unraveling.

Furthermore, Iran’s reported attempts to strike similar targets in U.S.-allied Gulf countries hosting American bases compound the regional danger. This tit-for-tat escalation against infrastructure threatens to drag neighboring civilian populations into the crossfire, further multiplying the violations of international humanitarian law across the Middle East.

As the strikes stretch into a second week, the international community, including legal advisors within the Pentagon and allied nations, must urgently scrutinize the target selection process. Transparency regarding the military justification for hitting water plants and bridges is not just a matter of public relations; it is a legal obligation.

War, even when deemed necessary by a state, is not a legal vacuum. The destruction of a drinking-water facility is a stark reminder that the laws of armed conflict were designed precisely for the fog of war, to preserve a baseline of humanity. If the U.S. and Iran continue to treat civilian infrastructure as legitimate battlegrounds, the ultimate casualty will be the international legal order itself.