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Daily Water Watch: La Plata at 43.00 m

Published Oct 20, 2026, 6:06 AM AST787daily · Original analysis

At a glance

  • Carraízo fell 1 cm to 40.86 m, in the Safe band (Seguridad), 1.16 m above the Watch line (Observación)
  • La Plata fell 7 cm to 43.00 m, in the Adjustments band (Ajustes); at this week’s pace, about 30 days until it reaches the Control line
  • Carraízo is falling, after a rise, averaging 1.3 cm a day over the past week; 1.68 in of rain over the watershed this week
  • Day 75 of the metro rotation, the San Juan area’s rationing schedule, with interruptions paused since September 2, and the Puerto Rico Aqueduct and Sewer Authority (AAA) has not canceled it; the plan began August 7; levels from the chart AAA publishes at 5:00 AM

Why this matters: The number that matters is the gap to the next band line: 1.16 m for Carraízo, 2.50 m for La Plata. Straight-line dates move every day; the daily check is the point.

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San Juan's rationing plan, zones and calendar

This morning’s 5:00 chart from AAA shows Carraízo at 40.86 meters, down 1 centimeter from yesterday. La Plata is at 43.00 meters, down 7 centimeters from yesterday.

Service today

Day 75 of the metro rotation, the San Juan area’s rationing schedule, with interruptions paused since September 2, and AAA has not canceled it.

AAA’s Cedro Arriba plan in Naranjito is in effect: Zone C and Zone D take turns every 48 hours; Zone C has water until Thursday at 6:00 AM.

AAA has posted no plan change, open outage or water-quality notice in the last three days.

Every notice AAA posts is on the water page, in its own words.

Reservoirs

Carraízo: down 1 cm

Carraízo slipped overnight. This morning’s chart puts it at 40.86 meters, down 1 centimeter from yesterday, in the Safe band (Seguridad). The next line on the chart, into the Watch band (Observación), sits at 39.70 meters, 1.16 meters below this morning’s reading.

Adjustments Watch Safe 37.0 37.5 38.0 38.5 39.0 39.5 40.0 40.5 41.0 Aug 22 Sep 20 Oct 20 Oct 3, 40.70 m, USGS gauge at 5 AM, Safe Aug 22, 37.46 m, AdjustmentsAug 23, 37.41 m, −5 cm, AdjustmentsAug 24, 37.34 m, −7 cm, AdjustmentsAug 25, 37.32 m, −2 cm, AdjustmentsAug 26, 37.30 m, −2 cm, AdjustmentsAug 27, 37.26 m, −4 cm, AdjustmentsAug 28, 37.20 m, −6 cm, AdjustmentsAug 29, 37.14 m, −6 cm, AdjustmentsAug 30, 37.07 m, −7 cm, AdjustmentsAug 31, 37.14 m, +7 cm, AdjustmentsSep 1, 37.20 m, +6 cm, AdjustmentsSep 2, 38.92 m, +172 cm, WatchSep 3, 39.11 m, +19 cm, WatchSep 4, 39.09 m, −2 cm, WatchSep 5, 39.01 m, −8 cm, WatchSep 6, 38.94 m, −7 cm, WatchSep 7, 38.87 m, −7 cm, WatchSep 8, 38.83 m, −4 cm, WatchSep 9, 39.02 m, +19 cm, WatchSep 10, 39.07 m, +5 cm, WatchSep 11, 39.20 m, +13 cm, WatchSep 12, 39.19 m, −1 cm, WatchSep 13, 39.14 m, −5 cm, WatchSep 14, 39.16 m, +2 cm, WatchSep 15, 39.25 m, +9 cm, WatchSep 16, 39.23 m, −2 cm, WatchSep 17, 40.06 m, +83 cm, SafeSep 18, 40.64 m, +58 cm, SafeSep 19, 40.80 m, +16 cm, SafeSep 20, 40.81 m, +1 cm, SafeSep 21, 40.79 m, −2 cm, SafeSep 22, 40.75 m, −4 cm, SafeSep 23, 40.70 m, −5 cm, SafeSep 24, 40.68 m, −2 cm, SafeSep 25, 40.68 m, +0 cm, SafeSep 26, 40.67 m, −1 cm, SafeSep 27, 40.63 m, −4 cm, SafeSep 28, 40.58 m, −5 cm, SafeSep 29, 40.53 m, −5 cm, SafeSep 30, 40.51 m, −2 cm, SafeOct 1, 40.47 m, −4 cm, SafeOct 2, 40.60 m, +13 cm, SafeOct 4, 40.74 m, +4 cm, SafeOct 5, 40.72 m, −2 cm, SafeOct 6, 40.69 m, −3 cm, SafeOct 7, 40.65 m, −4 cm, SafeOct 8, 40.88 m, +23 cm, SafeOct 9, 40.94 m, +6 cm, SafeOct 10, 40.91 m, −3 cm, SafeOct 11, 40.96 m, +5 cm, SpillingOct 12, 40.86 m, −10 cm, SafeOct 13, 40.90 m, +4 cm, SafeOct 14, 40.94 m, +4 cm, SafeOct 15, 40.85 m, −9 cm, SafeOct 16, 40.87 m, +2 cm, SafeOct 17, 40.85 m, −2 cm, SafeOct 18, 40.85 m, +0 cm, SafeOct 19, 40.87 m, +2 cm, SafeOct 20, 40.86 m, −1 cm, Safe 40.86 m at ~1 cm/day Oct 14, 0.7 in of rainOct 16, 0.01 in of rainOct 17, 0.2 in of rainOct 18, 0.7 in of rainOct 19, 0.07 in of rain rain to 0.70 in
Carraízo since Aug 22, meters above sea level, shaded by AAA alert band, with daily rain from gauges the U.S. Geological Survey (USGS) runs within 12 km. Data: AAA Monitoreo Diario; hollow points are the USGS gauge's 5 AM reading on mornings AAA's chart has none (AAA's own record here starts Aug 22).
Show the numbers
  • Aug 22, 37.46 m, Adjustments
  • Aug 23, 37.41 m, −5 cm, Adjustments
  • Aug 24, 37.34 m, −7 cm, Adjustments
  • Aug 25, 37.32 m, −2 cm, Adjustments
  • Aug 26, 37.30 m, −2 cm, Adjustments
  • Aug 27, 37.26 m, −4 cm, Adjustments
  • Aug 28, 37.20 m, −6 cm, Adjustments
  • Aug 29, 37.14 m, −6 cm, Adjustments
  • Aug 30, 37.07 m, −7 cm, Adjustments
  • Aug 31, 37.14 m, +7 cm, Adjustments
  • Sep 1, 37.20 m, +6 cm, Adjustments
  • Sep 2, 38.92 m, +172 cm, Watch
  • Sep 3, 39.11 m, +19 cm, Watch
  • Sep 4, 39.09 m, −2 cm, Watch
  • Sep 5, 39.01 m, −8 cm, Watch
  • Sep 6, 38.94 m, −7 cm, Watch
  • Sep 7, 38.87 m, −7 cm, Watch
  • Sep 8, 38.83 m, −4 cm, Watch
  • Sep 9, 39.02 m, +19 cm, Watch
  • Sep 10, 39.07 m, +5 cm, Watch
  • Sep 11, 39.20 m, +13 cm, Watch
  • Sep 12, 39.19 m, −1 cm, Watch
  • Sep 13, 39.14 m, −5 cm, Watch
  • Sep 14, 39.16 m, +2 cm, Watch
  • Sep 15, 39.25 m, +9 cm, Watch
  • Sep 16, 39.23 m, −2 cm, Watch
  • Sep 17, 40.06 m, +83 cm, Safe
  • Sep 18, 40.64 m, +58 cm, Safe
  • Sep 19, 40.80 m, +16 cm, Safe
  • Sep 20, 40.81 m, +1 cm, Safe
  • Sep 21, 40.79 m, −2 cm, Safe
  • Sep 22, 40.75 m, −4 cm, Safe
  • Sep 23, 40.70 m, −5 cm, Safe
  • Sep 24, 40.68 m, −2 cm, Safe
  • Sep 25, 40.68 m, +0 cm, Safe
  • Sep 26, 40.67 m, −1 cm, Safe
  • Sep 27, 40.63 m, −4 cm, Safe
  • Sep 28, 40.58 m, −5 cm, Safe
  • Sep 29, 40.53 m, −5 cm, Safe
  • Sep 30, 40.51 m, −2 cm, Safe
  • Oct 1, 40.47 m, −4 cm, Safe
  • Oct 2, 40.60 m, +13 cm, Safe
  • Oct 3, 40.70 m, USGS gauge at 5 AM, Safe
  • Oct 4, 40.74 m, +4 cm, Safe
  • Oct 5, 40.72 m, −2 cm, Safe
  • Oct 6, 40.69 m, −3 cm, Safe
  • Oct 7, 40.65 m, −4 cm, Safe
  • Oct 8, 40.88 m, +23 cm, Safe
  • Oct 9, 40.94 m, +6 cm, Safe
  • Oct 10, 40.91 m, −3 cm, Safe
  • Oct 11, 40.96 m, +5 cm, Spilling
  • Oct 12, 40.86 m, −10 cm, Safe
  • Oct 13, 40.90 m, +4 cm, Safe
  • Oct 14, 40.94 m, +4 cm, Safe
  • Oct 15, 40.85 m, −9 cm, Safe
  • Oct 16, 40.87 m, +2 cm, Safe
  • Oct 17, 40.85 m, −2 cm, Safe
  • Oct 18, 40.85 m, +0 cm, Safe
  • Oct 19, 40.87 m, +2 cm, Safe
  • Oct 20, 40.86 m, −1 cm, Safe
  • Oct 14, 0.7 in of rain
  • Oct 16, 0.01 in of rain
  • Oct 17, 0.2 in of rain
  • Oct 18, 0.7 in of rain
  • Oct 19, 0.07 in of rain

Carraízo, October 20

Level today
40.86 mSafe band
Change since yesterday
−1 cm
To the Watch line
1.16 mline at 39.70 m
At this week's pace
months awaythe decline is very shallow

La Plata: down 7 cm

La Plata kept sliding. This morning’s chart puts it at 43.00 meters, down 7 centimeters from yesterday, in the Adjustments band (Ajustes). The next line on the chart, into the Control band, sits at 40.50 meters, 2.50 meters below this morning’s reading. At this week’s pace that is about 30 days away (at this pace, November 20: a projection, not a forecast; one wet afternoon moves it).

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.

Adjustments Watch Safe 40 42 44 46 48 50 52 Aug 22 Sep 20 Oct 20 Oct 3, 43.87 m, USGS gauge at 5 AM, Adjustments Aug 22, 45.42 m, WatchAug 23, 45.35 m, −7 cm, WatchAug 24, 45.28 m, −7 cm, WatchAug 25, 45.23 m, −5 cm, WatchAug 26, 45.15 m, −8 cm, WatchAug 27, 45.04 m, −11 cm, WatchAug 28, 44.93 m, −11 cm, WatchAug 29, 44.83 m, −10 cm, AdjustmentsAug 30, 44.72 m, −11 cm, AdjustmentsAug 31, 44.67 m, −5 cm, AdjustmentsSep 1, 44.59 m, −8 cm, AdjustmentsSep 2, 44.59 m, +0 cm, AdjustmentsSep 3, 44.59 m, +0 cm, AdjustmentsSep 4, 44.57 m, −2 cm, AdjustmentsSep 5, 44.54 m, −3 cm, AdjustmentsSep 6, 44.52 m, −2 cm, AdjustmentsSep 7, 44.46 m, −6 cm, AdjustmentsSep 8, 44.40 m, −6 cm, AdjustmentsSep 9, 44.32 m, −8 cm, AdjustmentsSep 10, 44.24 m, −8 cm, AdjustmentsSep 11, 44.14 m, −10 cm, AdjustmentsSep 12, 44.25 m, +11 cm, AdjustmentsSep 13, 44.26 m, +1 cm, AdjustmentsSep 14, 44.40 m, +14 cm, AdjustmentsSep 15, 44.46 m, +6 cm, AdjustmentsSep 16, 44.40 m, −6 cm, AdjustmentsSep 17, 44.36 m, −4 cm, AdjustmentsSep 18, 44.40 m, +4 cm, AdjustmentsSep 19, 44.61 m, +21 cm, AdjustmentsSep 20, 44.66 m, +5 cm, AdjustmentsSep 21, 44.70 m, +4 cm, AdjustmentsSep 22, 44.72 m, +2 cm, AdjustmentsSep 23, 44.68 m, −4 cm, AdjustmentsSep 24, 44.63 m, −5 cm, AdjustmentsSep 25, 44.56 m, −7 cm, AdjustmentsSep 26, 44.47 m, −9 cm, AdjustmentsSep 27, 44.39 m, −8 cm, AdjustmentsSep 28, 44.31 m, −8 cm, AdjustmentsSep 29, 44.22 m, −9 cm, AdjustmentsSep 30, 44.13 m, −9 cm, AdjustmentsOct 1, 44.04 m, −9 cm, AdjustmentsOct 2, 43.96 m, −8 cm, AdjustmentsOct 4, 43.79 m, −8 cm, AdjustmentsOct 5, 43.71 m, −8 cm, AdjustmentsOct 6, 43.70 m, −1 cm, AdjustmentsOct 7, 43.68 m, −2 cm, AdjustmentsOct 8, 43.62 m, −6 cm, AdjustmentsOct 9, 43.54 m, −8 cm, AdjustmentsOct 10, 43.52 m, −2 cm, AdjustmentsOct 11, 43.50 m, −2 cm, AdjustmentsOct 12, 43.45 m, −5 cm, AdjustmentsOct 13, 43.45 m, +0 cm, AdjustmentsOct 14, 43.50 m, +5 cm, AdjustmentsOct 15, 43.47 m, −3 cm, AdjustmentsOct 16, 43.39 m, −8 cm, AdjustmentsOct 17, 43.29 m, −10 cm, AdjustmentsOct 18, 43.18 m, −11 cm, AdjustmentsOct 19, 43.07 m, −11 cm, AdjustmentsOct 20, 43.00 m, −7 cm, Adjustments 43.00 m at ~8 cm/day Oct 14, 0.01 in of rainOct 15, 0.01 in of rainOct 17, 0.01 in of rainOct 18, 0.2 in of rain rain to 0.20 in
La Plata since Aug 22, meters above sea level, shaded by AAA alert band, with daily rain from gauges USGS runs within 12 km. Data: AAA Monitoreo Diario; hollow points are the USGS gauge's 5 AM reading on mornings AAA's chart has none (AAA's own record here starts Aug 22).
Show the numbers
  • Aug 22, 45.42 m, Watch
  • Aug 23, 45.35 m, −7 cm, Watch
  • Aug 24, 45.28 m, −7 cm, Watch
  • Aug 25, 45.23 m, −5 cm, Watch
  • Aug 26, 45.15 m, −8 cm, Watch
  • Aug 27, 45.04 m, −11 cm, Watch
  • Aug 28, 44.93 m, −11 cm, Watch
  • Aug 29, 44.83 m, −10 cm, Adjustments
  • Aug 30, 44.72 m, −11 cm, Adjustments
  • Aug 31, 44.67 m, −5 cm, Adjustments
  • Sep 1, 44.59 m, −8 cm, Adjustments
  • Sep 2, 44.59 m, +0 cm, Adjustments
  • Sep 3, 44.59 m, +0 cm, Adjustments
  • Sep 4, 44.57 m, −2 cm, Adjustments
  • Sep 5, 44.54 m, −3 cm, Adjustments
  • Sep 6, 44.52 m, −2 cm, Adjustments
  • Sep 7, 44.46 m, −6 cm, Adjustments
  • Sep 8, 44.40 m, −6 cm, Adjustments
  • Sep 9, 44.32 m, −8 cm, Adjustments
  • Sep 10, 44.24 m, −8 cm, Adjustments
  • Sep 11, 44.14 m, −10 cm, Adjustments
  • Sep 12, 44.25 m, +11 cm, Adjustments
  • Sep 13, 44.26 m, +1 cm, Adjustments
  • Sep 14, 44.40 m, +14 cm, Adjustments
  • Sep 15, 44.46 m, +6 cm, Adjustments
  • Sep 16, 44.40 m, −6 cm, Adjustments
  • Sep 17, 44.36 m, −4 cm, Adjustments
  • Sep 18, 44.40 m, +4 cm, Adjustments
  • Sep 19, 44.61 m, +21 cm, Adjustments
  • Sep 20, 44.66 m, +5 cm, Adjustments
  • Sep 21, 44.70 m, +4 cm, Adjustments
  • Sep 22, 44.72 m, +2 cm, Adjustments
  • Sep 23, 44.68 m, −4 cm, Adjustments
  • Sep 24, 44.63 m, −5 cm, Adjustments
  • Sep 25, 44.56 m, −7 cm, Adjustments
  • Sep 26, 44.47 m, −9 cm, Adjustments
  • Sep 27, 44.39 m, −8 cm, Adjustments
  • Sep 28, 44.31 m, −8 cm, Adjustments
  • Sep 29, 44.22 m, −9 cm, Adjustments
  • Sep 30, 44.13 m, −9 cm, Adjustments
  • Oct 1, 44.04 m, −9 cm, Adjustments
  • Oct 2, 43.96 m, −8 cm, Adjustments
  • Oct 3, 43.87 m, USGS gauge at 5 AM, Adjustments
  • Oct 4, 43.79 m, −8 cm, Adjustments
  • Oct 5, 43.71 m, −8 cm, Adjustments
  • Oct 6, 43.70 m, −1 cm, Adjustments
  • Oct 7, 43.68 m, −2 cm, Adjustments
  • Oct 8, 43.62 m, −6 cm, Adjustments
  • Oct 9, 43.54 m, −8 cm, Adjustments
  • Oct 10, 43.52 m, −2 cm, Adjustments
  • Oct 11, 43.50 m, −2 cm, Adjustments
  • Oct 12, 43.45 m, −5 cm, Adjustments
  • Oct 13, 43.45 m, +0 cm, Adjustments
  • Oct 14, 43.50 m, +5 cm, Adjustments
  • Oct 15, 43.47 m, −3 cm, Adjustments
  • Oct 16, 43.39 m, −8 cm, Adjustments
  • Oct 17, 43.29 m, −10 cm, Adjustments
  • Oct 18, 43.18 m, −11 cm, Adjustments
  • Oct 19, 43.07 m, −11 cm, Adjustments
  • Oct 20, 43.00 m, −7 cm, Adjustments
  • Oct 14, 0.01 in of rain
  • Oct 15, 0.01 in of rain
  • Oct 17, 0.01 in of rain
  • Oct 18, 0.2 in of rain

La Plata, October 20

Level today
43.00 mAdjustments band
Change since yesterday
−7 cm
To the Control line
2.50 mline at 40.50 m
At this week's pace
about 30 daysat this pace: November 20

Cidra: the other rationing reservoir

Level today
400.64 mWatch band
Change since yesterday
0 cm
To the Adjustments line
0.41 mline at 400.23 m
At this week's pace
holding

Outlook

What the numbers say

The week’s pattern splits the three reservoirs apart. Carraízo, the big metro supplier, has stopped gaining: after climbing 4.2 cm a day the week before, it is now slipping 1.3 cm a day. That is a pause in a long recovery rather than a reversal, and at this pace the Watch line is more than two months away (arithmetic, not a forecast). Cidra is effectively flat, with the week’s movement inside chart-reading noise, even though nearly 2 inches of rain fell around it, most on October 18. That rain barely registered in the next morning’s reading.

La Plata is the one to watch. Its decline has sped up to 8.3 cm a day from 3.8 cm the week before, six straight mornings lower, and it has lost 355 cm since August 7. It received little rain, 0.23 in, which explains why nothing offset the draw. Continuing at this week’s rate would bring it to the Control line around November 20, though that date is a straight-line projection and would shift if the pace eases or rain arrives.

What to watch

  • Naranjito: whether AAA extends its Cedro Arriba plan (the calendar runs through October 31), changes the phase or ends it.

Lake levels

The gauge USGS runs at Carraízo read 40.87 meters at 5:45 AM. The gauge USGS runs at La Plata read 43.00 meters at 5:45 AM. The gauge USGS runs at Cidra read 400.64 meters at 5:45 AM.

The gauges report every quarter hour and their readings are provisional; the bands are measured on AAA’s 5:00 chart.

How we read the data

This is the 64th Daily Water Watch (yesterday’s is here). The levels update every morning on the water page.

Levels: AAA’s daily reservoir chart, October 20. Rain: gauges USGS runs within 12 km of each reservoir. Day counts start August 7, when the metro rotation took effect. Straight-line dates are arithmetic, not forecasts. How we report.

In context

About this analysis
Cite this

Source: 787daily, “Daily Water Watch: La Plata at 43.00 m”, Oct 20, 2026, https://787daily.com/news/2026-10-20-daily-water-watch-la-plata-at-43-00-m/

Numbers from
AAA's 5 AM reservoir chart, validated daily
Use our data
Today (JSON) · Reservoir history (CSV).Free to reuse under CC BY 4.0: credit 787daily.com with a link.

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