Mauritania, Kuwait and Jordan have the least secure water supplies, according to a ranking on Tuesday that says shortages in the Middle East and North Africa might cause political tensions and even higher oil prices.
The list, by British risk analysis group Maplecroft, said businesses needed to take more account of water security in investment decisions due to rising demand from a growing population and other impacts such as climate change.
It said Mauritania in West Africa had the least secure supplies of about 160 nations reviewed, followed by Kuwait, Jordan, Egypt, Israel, Niger, Iraq, Oman and the United Arab Emirates.
"Extreme water security risks across the Middle East and North Africa may lead to further increases in global oil prices and heightened political tensions in the future," Maplecroft said in a statement.
Many OPEC oil producers, including Saudi Arabia in 13th place, faced stresses on supplies.
Water from aquifers is often injected into oil reservoirs, for instance, to raise pressure and enhance oil recovery. As aquifers are depleted, water shortages could push up oil prices, Maplecroft risk analyst Tom Styles said.
Water from desalination plants or water piped from the sea would be more expensive, he said.
Mauritania was top since it has only one year-round river, the Senegal, and "aside from a small number of oases and wadis, the country is almost entirely dry," the report said. Population growth was forecast at 3 percent a year, boosting demand.
At the other end of the list, Sweden, Guyana, Canada and Russia are among those with the most secure supplies.
The ranking seeks to quantify factors such as population growth, dependence on supplies from abroad and current water intensity in the economy. March 22 is World Water Day in the UN calendar.
It noted efforts by businesses such as water recycling by Devon Energy in North Texas, low-water factories by retailer Marks & Spencer or targets for limiting water use by miner Rio Tinto .