Ostrom’s main focus was examining how common pool resources could be managed. She explained that common pool resources included lakes and fisheries because they could not be easily divided into private property, meaning they had to be managed by some of form of collective agreement. Her work, and that of her husband Vincent Ostrom, started by looking at water tables around Los Angeles. Immortalised in the Roman Polanski film China Town, different users were in danger of taking too much water from the system. If too much water was taken, the water table would fall and salt water would be sucked in, destroying the system. The Ostroms found that water users formed associations and, despite difficult challenges, found ways of co-operating to preserve the system.