With Cape Town on the verge of becoming the world’s first major metropolis to run out of water, international attention has turned to the city’s efforts to prevent Day Zero.

But throughout South Africa, several other major cities are also at risk of running dry due to years of drought, inadequate infrastructure, and excessive water use, according to reports by researchers and municipal water departments.

Take Action: Call on World Leaders to Prioritize Sanitation and Hygiene

In Johannesburg, South Africa’s biggest city, the municipal government released a statement asking residents to “reduce their water consumption patterns as water usage has increased at an alarming rate.”

The city issued significant water restriction notices nearly a year ago and continues to urge residents to shower for less than two minutes and flush the toilet only “when necessary.”

#LEVEL1WaterRestriction
You’re ONLY allowed to water gardens between 18h00- 06h00am. pic.twitter.com/XmcsleUsrX

— Johannesburg Water (@JHBWater) January 22, 2018

Read More: Cape Town Is About to Run Out of Water

Dams that provide water for residents of Durban and Port Elizabeth, two of the countries other massive municipalities, are only about a quarter full and a dam in the Kwazu-Natal region has reached a critically low level. That means they have only slightly more water available than the main reservoirs serving Cape Town.

Poor South Africans, especially the millions of black citizens in slum-like townships constructed during the Apartheid era, will be hardest hit by water restrictions and shortages, according to reports. Already, waterborne diarrheal diseases and foodborne illnesses flourish in conditions where clean water and reliable sanitation systems are out of reach.

In the past year, for example, at least 820 South Africans have been infected with listeriosis, an illness that often spreads when people don’t wash after handling contaminated food.

Water rationing, though vital to staving off Day Zero, often prevents people from washing their hands, food, or containers, thus exposing them to more dangerous bacteria.

Around the world, access to clean water reflects inequalities based on income level, race, and ethnicity. Roughly 2 billion people, including more than 750 million people in sub-Saharan Africa, lack reliable sources of clean drinking water.

Global Citizen campaigns on the United Nations’ Sustainable Development Goal Number 6, which aims to ensure safe, healthy, and reliable drinking water for everyone in the world. You can take action here.

But achieving that goal means combating climate change-related drought, building better water systems, and committing to ensuring clean water to every person in South Africa and the rest of the continent.

Read More: Cape Town Isn't the Only African City Facing Water Shortages

Currently, Nairobi, Kenya; Accra, Ghana; and other major African cities face water crises of their own.

"Nairobi's water system was planned for a population of about half a million people, but it now has more than 4 million people," said John Ponsonby, associate director of infrastructure for Deloitte."Part of the problem with water is you need to think many years in advance ... You have to be able to cope with changes in climate."