The Cost Of Desalination

Cost QuoteWest Basin has been studying the cost of ocean water desalination since 1947 when West Basin was formed to present. Over the years several advances in the desalination technology have brought the costs down significantly. When studying the cost of desalination the bulk contributor is energy consumption and power rates to produce the water. It takes about 4,000 kWh to produce one (1) Acre-Foot of water utilizing ocean water desalination. The energy consumption for other drinking water supplies can range from 3,500 kWh/AF for State Water Project water, 2,500kWh/AF Colorado River Aqueduct water, and 1,500kWh/AF for Indirect Potable Reuse recycled water.

When assessing the cost for ocean water desalination or any of the other supplies mentioned, the power cost for the project is a large component to bringing down the cost. Access to inexpensive sources of power and on-site power generation (ie renewables) with long term fixed agreements can help keep costs low.


The cost for West Basin’s responsible ocean water desalination program has been estimated to be $1,600-$1,900 per Acre-Foot for locally reliable, drought proof drinking water. The range of costs is dependent on how large of a facility is built as there are economic benefits if a large plant is built to have access to economies of scale. The $1,900 cost would be a conservative estimate for a 20 Million Gallon a Day (MGD) facility into West Basin’s local service area. The lower cost option of $1,600 would be for a 60 MGD regional facility. A regional facility would only be built if West Basin had a large regional partner who would be able to take some of the water into a regional water distribution system.

West Basin’s current proposed responsible ocean water desalination project is for 20MGD of fresh water to be piped directly into the local distribution system. A 20 MGD facility would account for 10% of the water West Basin supplies to the service area. The West Basin service area is primarily serviced by imported water from the Metropolitan Water District of Southern California (MWD). West Basin buys the imported water directly from MWD at a rate of $923-$1,055/AF depending on Tier 1 or Tier 2 rates. West Basin sells the water to our 17 member agencies for between $1,229-$1,361. More information on West Basin’s rate structure can be found here.

When comparing the costs of responsible desalination to the drinking water West Basin sells to the 17 member agencies the increase in cost is between 15%-35% depending on the size of facility and rate structure. Although a potential rate increase of 35% might seem high, ocean water desalination would only account for 10% of the water flowing through the West Basin service area and would keep the costs down for individual rate payers. After evaluating several cost scenarios, West Basin has estimated the average monthly bill increase to a single family residence in the service area to be approximately $3/month, or the price of a Starbuck coffee.

West Basin remains committed to lowering the cost of responsible ocean water desalination by continuing to pursue federal, state and local grant money, including money approved and allocated in the Proposition 1 through the 2014 California vote. West Basin is exploring opportunities in low fixed rate power costs through self-generation, renewable power, and long term fixed rate power grid charges.