The US Drought Monitor map dated September 1 puts 65 of 78 municipios in at least moderate drought (D1). The worst tier, D3 extreme drought, covers 40 of them, led by Aibonito, Canóvanas and Carolina.
69 of the 78 municipios are at least abnormally dry, 88.5% of the island. This is the first edition of the series, so there is no week-over-week comparison yet; from the next map onward this desk tracks which municipios moved.
In the week to September 5, the biggest reservoir fall was La Plata, down 0.29 m (Ajustes band), and the biggest rise Patillas, up 2.52 m. The tables below carry every category, the municipios in the worst tier and each reservoir’s week.
By category
| Category | Municipios | Share of 78 |
|---|---|---|
| No drought | 9 | 11.5% |
| D0 abnormally dry | 4 | 5.1% |
| D1 moderate drought | 9 | 11.5% |
| D2 severe drought | 16 | 20.5% |
| D3 extreme drought | 40 | 51.3% |
| D4 exceptional drought | 0 | 0% |
Where the map is worst
| Municipio | Category | Share of area |
|---|---|---|
| Aibonito | D3 extreme drought | 100% |
| Canóvanas | D3 extreme drought | 100% |
| Carolina | D3 extreme drought | 100% |
| Coamo | D3 extreme drought | 100% |
| Culebra | D3 extreme drought | 100% |
| Guánica | D3 extreme drought | 100% |
| Gurabo | D3 extreme drought | 100% |
| Juana Díaz | D3 extreme drought | 100% |
The 8 municipios with the largest share of their area at D3, of 40 in that tier.
The reservoirs
| Reservoir | Level (m) | 7-day change | AAA band |
|---|---|---|---|
| La Plata | 44.54 | -0.29 m | Ajustes |
| Guayo | 442.35 | -0.25 m | Seguridad |
| Loco | 69.56 | -0.15 m | Seguridad |
| Dos Bocas | 89.70 | -0.08 m | Seguridad |
| Guajataca | 195.91 | +0.01 m | Seguridad |
| Garzas | 736.05 | +0.02 m | Seguridad |
| Toa Vaca | 147.21 | +0.07 m | Seguridad |
| Cidra | 400.17 | +0.13 m | Ajustes |
| Cerrillos | 167.53 | +0.22 m | Seguridad |
| Carite | 542.00 | +0.30 m | Seguridad |
| Fajardo | 46.69 | +0.36 m | Observación |
| Río Blanco | 24.85 | +0.49 m | Observación |
| Guayabal | 102.92 | +0.51 m | Seguridad |
| Lucchetti | 171.57 | +0.53 m | Seguridad |
| Guineo | 902.27 | +0.78 m | Desborde |
| Caonillas | 251.28 | +0.82 m | Seguridad |
| Matrullas | 734.30 | +1.18 m | Seguridad |
| Carraízo | 39.01 | +1.87 m | Observación |
| Patillas | 65.86 | +2.52 m | Seguridad |
Levels are AAA’s chart readings for September 5; the change is against August 29.
The full map, coloured by category, is on the water page, next to the reservoir board and the rationing schedule. This is the first Drought Watch.
Source: US Drought Monitor (NDMC, USDA, NOAA) county statistics for Puerto Rico, map dated 2026-09-01; reservoir levels from AAA’s published chart. USDM categories are a weekly expert synthesis of indicators, not a rainfall total; municipio shares are area-weighted.