The dam filled up and your tap is still shut: water stopped being a rain problem

As of the 20 July 2026 cutoff, the Cutzamala System reached 72.54% storage —566 million cubic meters— 14.2 percentage points above the same period in 2025 and its best level since the 2024 crisis. The figure comes from the official report of the Valley of Mexico Basin Organization (Conagua) and was cross-checked across four independent outlets citing the same cutoff with identical figures.

That same week, on 18 July, SACMEX kept rationing programs active in at least 10 boroughs of Mexico City, without official notices specifying the technical cause. According to SACMEX figures cited by UNAM Global, of the 32,000 liters per second the city captures, around 12,800 —40%— are lost before reaching their destination, mainly through leaks in the distribution network.

Five days before that cutoff, on 15 July, the Federal Official Gazette (DOF) published the first stage of regularization for national water concession and allocation titles that expired between 2009 and the date of the agreement: a 365-calendar-day window —through 15 July 2027— for domestic, public urban, agricultural, livestock and aquaculture uses, requiring recent operational works and an installed meter. Industrial and agro-industrial use is excluded from this first stage. It is the first operational piece of the December 2025 reform to the National Water Law, which replaced the free transmission of rights with reassignment under Conagua's intervention.

Three facts from the same month, across three different registers —hydrological, operational and regulatory— that together say something none of them says alone.

Water scarcity in the Mexican capital was narrated for years as a rain problem: drought, low reservoirs, waiting for the rainy season. The full reservoir removes that alibi and exposes the real tension, which isn't one but two, running in parallel.

The first is physical: a distribution network that loses around 40% of what it captures, and an aquifer the Cutzamala doesn't replenish and was never designed to replenish, against an urban and industrial demand that plans as if supply would normalize on its own just because it rained. The exact attribution of the persisting rationing —how much is network, how much is aquifer, how much is management— isn't specified in official notices, and this note doesn't resolve what the source doesn't resolve.

The second is regulatory: the concession title, treated for decades as inheritable, accumulable patrimony traded in an informal market, is starting to behave like a use-conditioned permit, reviewable by the State and subject to a window with an expiration date. The rain came back. Certainty about who the water belongs to, and under what rules, didn't.

For a mid-sized company in the Valley of Mexico basin whose operation depends on water, the map shifted on two planes at once, and neither resolves itself by waiting for the next rainy season.

On the physical plane: hotels and restaurants under rationing, light manufacturing with its own wells, and developers with permits in process are planning 2027 on an assumption —"it rained, it's resolved"— that the very persistence of rationing with a full reservoir contradicts. The bottleneck stopped being how much water there is and became where it travels.

On the legal plane: the concession title stopped being something you keep in a drawer or buy on the secondary market when needed. One that's expired and doesn't make it into the regularization window is lost with no way to recover it later; and industrial use, which doesn't even have a window in this first stage, keeps operating in irregularity under a regime that's already harder than the previous one and will foreseeably get harder still.