California is a coastal state in western USA. It has deserts to the east, but there is usually plenty of rainfall to provide water along the coast.
California has experienced drought since 2011. Irrigated crops use a lot of the freshwater supplies in the region. Rising temperatures, falling rainfall levels and a growing population are also contributing to the problem.
The drought has lowered groundwater levels. This can cause lots of problems, such as:
There are no official rules in California that stop property owners from pumping more water out of the ground. Groundwater limits are now being considered, but these couldn't be enforced until 2020. Until then, people are being encouraged to use less water.