What you need to know about the water crisis in Puerto Rico

U.S. citizens in the San Juan area are waiting hours in line for water.

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U.S. citizens in San Juan, Puerto Rico, are spending hours waiting for water trucks after water rationing went into effect amid drought on the island archipelago. Puerto Rico Gov. Jenniffer González declared a state of emergency in late July as the water in key dams dropped below levels that can support communities. 

Seven of the most populous of the 78 municipalities on the island archipelago are experiencing a rotating schedule of 48 hours – or more – without water, with more than 500,000 people affected. 

How did this water crisis get so bad? Read on to get up to speed. 

It’s been raining in Puerto Rico, so why isn’t there enough water? 

Seventy-two percent of the land area of Puerto Rico is experiencing drought, according to the U.S. Drought Monitor. But this water crisis isn’t just about a lack of rain: high temperatures, lack of dredging sedimentation in reservoirs, deteriorating infrastructure, and mismanagement have led to Puerto Rico facing one of its worst water crises since 2015. 

Another problem is that rain isn’t always falling in the right places. Rain in the west, south, or mountainous interior doesn’t necessarily benefit Carraízo, the main reservoir that supplies San Juan and the surrounding municipalities.

Yes. As Yale Climate Connections contributor Yessenia Funes explains in her newsletter (you should subscribe!), the Indigenous inhabitants of Puerto Rico chose the island for its plentiful rainfall. But as Puerto Rican journalist Manuel Guillama Capella points out, residents are now experiencing a culmination of decades of poor maintenance of collapsing infrastructure. 

“For more than three decades, the Puerto Rico Aqueduct and Sewer Authority has staggered from one crisis to the next,” he wrote in Spanish in an article published in Puerto Rico’s most-read newspaper, El Nuevo Día. “Fiscal crises, operational problems, failed privatizations, poor planning, and inefficient execution of capital improvement projects that, in theory, should provide the stability needed for the production, treatment, and supply of drinking water service required by nearly 1.3 million households and businesses across Puerto Rico.”

Has Puerto Rico experienced a water crisis before? 

A 2015 drought crisis caused prolonged rationing and disrupted daily life for millions of people – and disrupted farming. Although the current situation doesn’t exactly replicate the 2015 drought in terms of duration and geographical areas affected, it shares troubling features: a sustained decline in water sources, limited recovery after isolated rainstorms, pressure on filtration plants, and prolonged service interruptions. 

This year, extreme heat has made the problem worse by increasing water consumption and driving greater evaporation from reservoirs and other bodies of water.

What is the government doing about the problem? 

The 2015 drought was a warning that still hasn’t fully translated into public policy.

Even before the water crisis, approximately 65% of potable watereither did not reach clients due to water leaks or went unbilled. 

The González administration has faced ongoing criticism of its handling of the situation, including a lack of communication about where and when there will be water rationing. Recently, unionized employees of the Puerto Rico Aqueduct and Sewer Authority went on strike, stating that they can no longer live on $10.50/hour. 

The Federal Emergency Management Agency, or FEMA, announced that it would send water trailers to Puerto Rico to assist with water distribution, ABC reported. 

What are individuals doing? 

Unlike during the 2015 drought, in 2026, far more households have cisterns. This preparedness marks real progress, because it enables many people to cope with service interruptions. But it also introduces an added challenge for managing rationing. Cistern filling before or right after interruption periods can create demand spikes, reduce system pressure, and limit the effectiveness of conservation measures. 

On the other hand, cisterns aren’t a solution for many people living around San Juan, the epicenter of this year’s crisis. It’s not easy to install such a system in urban areas, not to mention the cost. In a place where the average household income is just over $26,000, price can put a cistern out of reach for many people. 

There is no reliable data on how many Puerto Rican households have access to private water reserves like catchment systems and cisterns. 

Is El Niño affecting the amount of rainfall?

El Niño alone doesn’t determine rainfall in Puerto Rico. Its effects depend on the season, tropical Atlantic temperatures, the position of the subtropical high, trade winds, and other atmospheric patterns. Still, it can alter the regional distribution of rainfall and increase uncertainty. Because of climate change, precipitation patterns in the Caribbean have shifted, moving mostly toward the western part of the island. 

How does sediment affect water supply?

Many reservoirs have lost much of their original capacity as a result of sediment flowing in. Hurricane María, which was made more intense by climate change, worsened this problem by triggering tens of thousands of landslides and moving huge volumes of soil, logs, branches, and other debris into rivers, streams, and tributary watersheds. Some of that material ended up in these reservoirs, accelerating sediment buildup and reducing the volume of water stored.

What about desalination as a solution?

Desalination plants convert salty or brackish water into drinking water. But in this case, desalination doesn’t seem to be a potential solution. It can be useful, but it requires high-energy consumption on an island with already failing infrastructure. Desalination also requires a lot of investment, specialized maintenance, and proper brine management. 

Can we seed the clouds?

Cloud seeding isn’t a viable primary operational response, either. On a small tropical island, with fast-evolving clouds, highly variable trade winds, and small watersheds, directing rain toward a specific reservoir poses real scientific and operational challenges. Cloud seeding efforts in 2015 produced no verifiable benefits for Puerto Rico and showed no significant contribution to reservoir recovery.

What can be done better to manage Puerto Rico’s water? 

Ideally, Puerto Rico would have a daily public dashboard for each system showing reservoir level, estimated usable volume, trend, inflows and outflows, watershed rainfall, withdrawals, affected municipalities, and projections. Better coordination between the utility companies that supply the archipelago’s drinking water, the Department of Natural and Environmental Resources, the National Weather Service, the island’s municipalities, the agricultural sector, universities, and community organizations could also help improve water use. 

Many of these actions are already outlined in Puerto Rico’s Climate Change Mitigation, Adaptation, and Resilience Plan, released in 2024 after input from public hearings and Puerto Rican experts, including an author (Rafael Méndez Tejeda) of this article. The document lays out a path to reduce vulnerabilities, anticipate risks, and strengthen resilience. But the lack of legislative action has left this preventive planning off the table for this situation and any other extreme weather events that will occur in the future. 

This article was originally published by Yale Climate Connections.

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