How does rainwater harvesting reduce demand on public water supplies?

Rainwater harvesting reduces demand on public water supplies by providing an alternative, localized source of water for nonpotable functions. By capturing and storing precipitation that would otherwise be directed into storm sewers, households and businesses can utilize this collected water for tasks such as irrigating landscaping, flushing toilets, washing cars, and laundering clothes.12

This practice lessens the reliance on municipal systems for potable water, which is particularly beneficial in densely populated regions facing water scarcity. Furthermore, by diverting runoff from hard surfaces like roofs and roads, these systems help mitigate the strain on urban stormwater infrastructure, which often struggles to manage large volumes of water during heavy rainfall. While some jurisdictions place restrictions on collection due to water rights concerns, many municipalities actively encourage or subsidize the use of rain barrels and other harvesting technologies to promote more sustainable water management.21