Day 36 of the metro rotation plan — interruptions paused since September 2, plan still in force. This morning’s 5:00 chart from the Autoridad de Acueductos y Alcantarillados shows Carraízo at 39.19 meters — down 1 centimeter from yesterday, and La Plata at 44.25 meters — up 11 centimeters from yesterday.
This is the 33th entry in our daily chart check (yesterday’s is here), built the same way every morning — from AAA’s own numbers, read off its charts for our reservoir board.
Carraízo: down 1 cm
Carraízo kept sliding. This morning’s chart puts it at 39.19 meters — down 1 centimeter from yesterday, in the observación band. The next line on the chart — into the ajustes band — sits at 38.50 meters, 0.69 meters below this morning’s reading.
Carraízo · September 12
- Level today
- 39.19 mband: observación
- Change since yesterday
- -1 cm
- To the ajustes line
- 0.69 mline at 38.50 m
- At the current pace
- months awaythe decline is very shallow
La Plata: a rise
La Plata gained ground overnight. This morning’s chart puts it at 44.25 meters — up 11 centimeters from yesterday, in the ajustes band. The next line on the chart — into the control band — sits at 40.50 meters, 3.75 meters below this morning’s reading.
If your water comes from La Plata — Dorado, Guaynabo, Naranjito, Toa Alta, Toa Baja, Vega Alta, Bayamón, Cataño, Corozal — this is the reservoir to watch; AAA lists 130,828 client accounts on it.
La Plata · September 12
- Level today
- 44.25 mband: ajustes
- Change since yesterday
- +11 cm
- To the control line
- 3.75 mline at 40.50 m
- At the current pace
- rising
What the numbers say
Carraízo’s climb has lost most of its steam: the past week’s average gain is well below the pace of the week before, a clear slowdown even though the reservoir is still trending upward toward the seguridad line above. Rain in the area hasn’t been the driver — the wettest day this week was actually followed by a drop in the reading, suggesting the recent rise has more to do with reservoir management than runoff. Cidra shows a similar pattern, still rising but at a gentler rate than its prior week, and sitting just above the ajustes line beneath it. There, rain does seem to be helping — the heaviest rain day this week was followed by a solid overnight gain, and the response has been building day over day.
La Plata is the outlier: its decline is accelerating rather than easing, falling faster this week than the week before despite a handful of rainy days nearby. Each of the wetter mornings there was followed by a lower reading the next day, not higher, underscoring that rainfall in that watershed isn’t translating into recovery right now. Projected forward at arithmetic pace, none of the three basins are near an imminent band change, but the diverging trends — La Plata sliding faster while Carraízo and Cidra rise more slowly — are worth watching over the coming weeks.
What to watch
- Carraízo: whether the rise survives a dry week — this week’s gain came with 1.82 in of rain nearby.
- Cidra: whether the rise survives a dry week — this week’s gain came with 4.51 in of rain nearby.
The other rationing reservoir
Cidra · September 12
- Level today
- 400.27 mband: observación
- Change since yesterday
- 0 cm
- To the ajustes line
- 0.04 mline at 400.23 m
- At the current pace
- holding
Numbers from AAA’s Monitoreo Diario chart of 2026-09-12, read each morning for our reservoir board — where the levels, the bands, and the live rain gauges update daily. Rain figures are USGS gauges within 12 km of each reservoir (a proximity proxy, not a basin measurement). Day counts start 2026-08-08, when the metro rotation took effect. Straight-line dates are arithmetic, not forecasts. The analysis paragraphs are drafted by Claude from the computed figures and checked number-by-number against them before publishing.