The cost of imported water varies during years of drought and allocation from the State Water Board. The vulnerability of imported water to drought and environmental regulation has been repeatedly shown, which is why purified is a safe and reliable source for our future water supply. On an annual basis, the purification center costs $3.6-$5.5 million to operate and produce 8 million gallons of purified water per day (MGD). A desalination plant, which purifies seawater to produce drinking water, can cost anywhere from $11.2- $17.6 million dollars per year to operate and produce 8 MGD. In terms of energy usage, the pressure needed to run the reverse osmosis feed pumps is 190 pounds per square inch when purifying reused water. Desalination requires the pressure to be increased to 900-5,000 pounds per square inch, which significantly increases the energy usage and costs.