Gripped by a prolonged drought, Arizona faces possible cuts to its main water supply in the next 18 months.

Residents, however, face none of the restrictions that neighboring California has imposed this year.

The desert state has been able to withstand a 15-year arid spell through long-term planning, conservation and a massive underground reserve that holds enough water to supply the state for a year.

But dropping water levels at Lake Mead, the largest water reservoir in the U.S., could prompt cuts that state-level officials are looking to avoid. The lake, formed by the Hoover Dam, has been dipping for years and federal officials say it could drop low enough by 2017 that it would trigger supply cuts to Arizona and Nevada.