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Reservoirs

Levels for the 19 reservoirs on AAA's daily bulletin

Guayo

Lares

Safety

442.23m

1,450.90 ft

0.27 m above Observation

Data as of August 23, 2026 · Reading taken at 5:00 AM

Compared with normal

0.01 m below normal for this date

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

Percentile 50 across 41 years of record.

Rank 290 of 582 readings from these dates. Rank 1 is the lowest.

The rank counts individual readings, not years.

Most recent year lower on this date: 2021.

Median
442.25 m
Minimum
11.64 m1980
Maximum
445.58 m2014
90th percentile
445.09 m

Level over time

Resolution follows the range: daily up to a year, weekly at five years, monthly across the whole record.

Guayo: level from July 25, 2026 to August 23, 2026, a net rise of 0.27 m.

August 23, 2026: 442.23 m.

Hover the chart or use the arrow keys to read a point.

From July 25, 2026 to August 23, 2026. Minimum 441.97 m, maximum 443.41 m.

The vertical scale runs from 441.50 m to 443.50 m and does not start at zero: these are metres above sea level.

The dashed lines are the alert bounds AAA publishes today. The record keeps no history of those bounds, so we do not know whether they were the same in the past.

Today the reservoir is in Safety.

4 bounds fall outside this chart’s scale.

Guayo: level from July 25, 2026 to August 23, 2026, a net rise of 0.27 m.
Datem
July 25, 2026441.97
July 26, 2026442.03
July 27, 2026442.14
July 28, 2026442.30
July 29, 2026442.37
July 30, 2026442.42
July 31, 2026442.48
August 1, 2026442.55
August 2, 2026442.58
August 3, 2026442.64
August 4, 2026442.67
August 5, 2026442.73
August 6, 2026442.76
August 7, 2026442.79
August 8, 2026442.85
August 9, 2026442.89
August 10, 2026442.91
August 11, 2026442.96
August 12, 2026443.10
August 13, 2026443.22
August 14, 2026443.29
August 15, 2026443.33
August 16, 2026443.37
August 17, 2026443.41
August 18, 2026443.18
August 19, 2026442.87
August 20, 2026442.53
August 21, 2026442.21
August 22, 2026442.17
August 23, 2026442.23

Projection

Disabled

This portal does not publish projections yet. Saying when a reservoir would reach its next phase is a claim about the future of a great many people's water, and before publishing one we want the rule for when it may and may not be made written down.

Every August 23 in the record

Compare another date

Hover the dots or use the arrow keys.

18 years of the 40 with a reading on August 23 were below the most recent level.

From 1980 to 2026.

The dashed line is this reservoir’s most recent level: 442.23 m on August 23, 2026.

The vertical scale runs from 0.00 m to 600.00 m and does not start at zero: these are metres above sea level.

Years with no reading on this date are not in the record and are left as empty space on the axis.

Years below the most recent level are marked with a filled dot.

This counts years. The rank in the block above counts readings.

18 years of the 40 with a reading on August 23 were below the most recent level.
Every August 23 in the recordm
198012.78
198118.33
198214.27
198316.06
1989441.23
1990435.47
1991439.15
1992437.16
1994436.08
1995437.42
1996439.30
1997439.00
1998443.01
1999442.61
2000443.55
2001440.68
2003438.24
2004443.24
2005445.11
2006439.91
2007441.97
2008442.44
2009442.02
2010444.54
2011445.22
2012445.07
2013445.01
2014444.66
2015442.47
2016444.50
2017443.38
2018442.73
2019444.19
2020444.52
2021441.64
2022445.14
2023445.05
2024445.10
2025445.08
2026442.23

When it has been in each phase

Hover the bands or use the arrow keys.

Each band is one run in one phase, since January 1, 2020.

The axis is calendar time, from January 1, 2020 to August 23, 2026. Stretches with no bulletin are left blank.

Current run

30 days in Safety, since July 25, 2026.

The longest run in Safety on record: 213 days, from November 11, 2008 to June 11, 2009.

Counts bulletin days, not calendar days.

Each band is one run in one phase, since January 1, 2020.
PhaseFromToBulletin days
OverflowJanuary 1, 2020January 17, 202017
SafetyJanuary 18, 2020January 19, 20202
OverflowJanuary 20, 2020January 23, 20204
SafetyJanuary 24, 2020January 30, 20207
OverflowJanuary 31, 2020February 16, 202017
SafetyFebruary 17, 2020March 8, 202021
OverflowMarch 9, 2020April 8, 202031
SafetyApril 9, 2020July 26, 2020104
OverflowJuly 27, 2020July 28, 20202
SafetyJuly 29, 2020July 30, 20202
OverflowJuly 31, 2020July 31, 20201
SafetyAugust 1, 2020August 26, 202026
OverflowAugust 27, 2020November 1, 202067
SafetyNovember 2, 2020November 15, 202014
OverflowNovember 16, 2020December 10, 202025
SafetyDecember 11, 2020January 3, 202124
OverflowJanuary 4, 2021January 14, 202111
SafetyJanuary 15, 2021February 8, 202125
ObservationFebruary 9, 2021February 15, 20217
SafetyFebruary 16, 2021February 21, 20216
ObservationFebruary 22, 2021March 12, 202119
Operational adjustmentsMarch 13, 2021March 24, 202112
ObservationMarch 25, 2021April 3, 202110
Operational adjustmentsApril 4, 2021April 4, 20211
ObservationApril 5, 2021April 26, 202122
Operational adjustmentsApril 27, 2021April 27, 20211
ObservationApril 28, 2021May 5, 20218
SafetyMay 6, 2021May 11, 20216
ObservationMay 12, 2021May 19, 20218
SafetyMay 20, 2021May 21, 20212
ObservationMay 22, 2021June 3, 202113
SafetyJune 4, 2021June 6, 20213
ObservationJune 7, 2021June 10, 20214
SafetyJune 11, 2021July 29, 202149
ObservationJuly 30, 2021August 6, 20218
SafetyAugust 20, 2021August 21, 20212
ObservationAugust 22, 2021September 8, 202118
SafetySeptember 9, 2021September 28, 202120
OverflowSeptember 29, 2021October 3, 20215
SafetyOctober 4, 2021October 20, 202117
OverflowOctober 21, 2021November 24, 202135
SafetyNovember 25, 2021December 17, 202123
OverflowDecember 18, 2021December 28, 202111
SafetyDecember 29, 2021February 13, 202247
ObservationFebruary 14, 2022February 16, 20223
SafetyFebruary 17, 2022June 1, 2022105
ObservationJune 2, 2022June 8, 20227
SafetyJune 9, 2022June 11, 20223
ObservationJune 12, 2022June 22, 202211
SafetyJune 23, 2022August 16, 202255
OverflowAugust 17, 2022August 18, 20222
SafetyAugust 19, 2022August 20, 20222
OverflowAugust 21, 2022November 20, 202292
SafetyNovember 21, 2022December 3, 202213
OverflowDecember 4, 2022December 9, 20226
SafetyDecember 10, 2022January 1, 202323
OverflowJanuary 2, 2023January 12, 202311
SafetyJanuary 13, 2023January 19, 20237
OverflowJanuary 20, 2023January 27, 20238
SafetyJanuary 28, 2023May 20, 2023113
OverflowMay 21, 2023June 9, 202320
SafetyJune 10, 2023August 19, 202371
OverflowAugust 20, 2023August 29, 202310
SafetyAugust 30, 2023September 10, 202312
OverflowSeptember 11, 2023October 10, 202330
SafetyOctober 11, 2023October 22, 202312
OverflowOctober 23, 2023November 8, 202317
SafetyNovember 9, 2023November 25, 202317
OverflowNovember 26, 2023December 23, 202328
SafetyDecember 24, 2023January 28, 202436
ObservationJanuary 29, 2024February 21, 202424
SafetyFebruary 22, 2024March 8, 202416
ObservationMarch 9, 2024March 24, 202416
SafetyMarch 25, 2024April 6, 202413
ObservationApril 7, 2024April 18, 202412
SafetyApril 19, 2024April 26, 20248
OverflowApril 27, 2024September 15, 2024142
SafetySeptember 16, 2024September 21, 20246
OverflowSeptember 22, 2024January 11, 2025112
SafetyJanuary 12, 2025January 28, 202517
OverflowJanuary 29, 2025February 4, 20257
SafetyFebruary 5, 2025March 13, 202537
OverflowMarch 14, 2025March 25, 202512
SafetyMarch 26, 2025April 5, 202511
OverflowApril 6, 2025April 7, 20252
SafetyApril 8, 2025April 29, 202522
OverflowApril 30, 2025May 12, 202513
SafetyMay 13, 2025May 17, 20255
OverflowMay 18, 2025May 26, 20259
SafetyMay 27, 2025June 5, 202510
OverflowJune 6, 2025June 20, 202515
SafetyJune 21, 2025July 7, 202517
OverflowJuly 8, 2025July 12, 20255
SafetyJuly 13, 2025August 10, 202529
OverflowAugust 11, 2025August 29, 202519
SafetyAugust 30, 2025August 31, 20252
OverflowSeptember 1, 2025September 9, 20259
SafetySeptember 10, 2025September 18, 20259
OverflowSeptember 19, 2025September 20, 20252
SafetySeptember 21, 2025September 23, 20253
OverflowSeptember 24, 2025November 12, 202550
SafetyNovember 13, 2025November 17, 20255
OverflowNovember 18, 2025November 22, 20255
SafetyNovember 23, 2025November 29, 20257
OverflowNovember 30, 2025December 29, 202530
SafetyDecember 30, 2025February 6, 202639
OverflowFebruary 7, 2026March 5, 202627
SafetyMarch 6, 2026March 27, 202622
OverflowMarch 28, 2026May 22, 202656
SafetyMay 23, 2026July 20, 202659
ObservationJuly 21, 2026July 24, 20264
SafetyJuly 25, 2026August 23, 202630

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.