Distributed water technologies offer benefits similar to those of distributed energy technologies. A typical American consumer uses approximately 570 liters (150 gallons) per day of drinking water in his or her household. Large central facilities treat and pump this water to homes. However, consumers use only a small fraction of this highly treated water for drinking. The rest is used for washing, watering, cooking, and flushing. With a distributed system, centralized facilities treat and distribute water only for drinking while on-site facilities harvest and prepare water for other end uses such as rain barrels that collect rain for watering lawns. With this approach, water treatment facilities’ burdens drop from 570 liters (150 gallons) per person per day to between 95 and 190 liters (25 to 50 gallons) per person per day. Reducing the volume of water pumped at a distance reduces the energy required. This approach only makes sense where there is local water like precipitation to harvest, so many desert communities might not be able to pursue this alternative. Like all distributed systems, integrated distributed water systems might be more resilient compared to the interdependent centralized systems in the event of a targeted attack or unfortunate natural incident.
As a counterpoint, centralized water treatment benefits from energy efficiency, which in turn benefits from an economy of scale. Therefore, distributed treatment of drinking water might increase the energy consumption per unit of water. However, energy savings from shorter pumping distances might overcome efficiency losses from smaller treatment volumes.