Puerto Rico Reservoirs

14 of 19 reservoirs fell in 24 hours

4 rose and one held level.

2 are in Operational adjustments: Carraízo and Cidra.

Data as of August 23, 2026 · the 5:00 AM reading.

19 of 19 reservoirs reporting

The 19 reservoirs

The 19 reservoirs on August 23, 2026.

Showing 19 of 19 reservoirs

Each figure is the reservoir seen from the side: the water rises to the measured level and the crest is drawn at the overflow point. The phase lines sit at the same height on every card, so the water is what moves and one reservoir can be compared with another. Ordered from least margin to most.

The same data as the chart, as a table.
Reservoir	Phase	Percent of range	24-hour change
Río Blanco	Observation	53%	-0.07 m
Toa Vaca	Safety	59%	-0.02 m
Cidra	Operational adjustments	61%	-0.01 m
Matrullas	Safety	64%	0.00 m
Fajardo	Observation	65%	-0.06 m
Guayo	Safety	66%	+0.07 m
Carraízo	Operational adjustments	68%	-0.05 m
La Plata	Observation	72%	-0.07 m
Lucchetti	Safety	73%	-0.08 m
Guayabal	Observation	74%	+0.02 m
Dos Bocas	Safety	79%	-0.11 m
Patillas	Safety	80%	-0.05 m
Cerrillos	Safety	81%	-0.06 m
Carite	Safety	89%	-0.02 m
El Guineo	Safety	90%	-0.05 m
Loco	Safety	92%	-0.01 m
Caonillas	Safety	95%	+0.01 m
Guajataca	Safety	95%	-0.02 m
Garzas	Safety	99%	+0.03 m

No mode compares heights between reservoirs. Every reservoir is read against its own thresholds.

Colour is never the only signal: the phase is written beside it in every mode.

Lowest against normal

Patillas

3.85 m below normal for this date

A ±7-day window around August 23, 2026, this reservoir's own most recent reading.

Selected by: the lowest percentile against normal, among reservoirs with 15 or more years of record

Largest 24-hour fall

Dos Bocas

-0.11 m

Selected by: the most negative 24-hour change in v_latest

Largest 24-hour rise

Guayo

+0.07 m

Selected by: the most positive 24-hour change in v_latest

AAA alert phases

Overflow — At capacity; the excess leaves over the spillway.
Safety — Normal operating level.
Observation — Below the safety mark; under monitoring.
Operational adjustments — AAA reduces withdrawal to stretch the reserve.
Control — Critical level.
Out of service — Below the point of reliable withdrawal.

How we read the data

Every figure on this portal is the 5:00 AM AST reading from the USGS gauge, every day, at every reservoir. AAA's daily bulletin is drawn at 4:55 AM and carries the freshest reading that had arrived by press time; the gauges transmit once an hour, and the 5:00 AM reading is published around 5:57 AM. On days when levels move quickly the two figures can therefore differ by about a centimetre. Each is correct for its own cut-off. Ours holds the same 24-hour interval every day, which is what makes our day-over-day changes directly comparable to one another.

We read the same USGS gauges that underpin the bulletin. The alert phases (Overflow, Safety, Observation, Operational adjustments, Control) are the thresholds AAA publishes for each reservoir; AAA prints them in Spanish, as Desborde, Seguridad, Observación, Ajustes and Control.

Source

Data: U.S. Geological Survey (USGS)

Provisional data

Provisional data: values are preliminary, have not been reviewed or approved by the U.S. Geological Survey, and are subject to revision or removal as the record is finalized. Do not use them for decisions involving personal or public safety, or property.

Daily reservoir level bulletin: Autoridad de Acueductos y Alcantarillados de Puerto Rico.

This portal is not an official channel of the Autoridad de Acueductos y Alcantarillados. For service notices, consult AAA.