FREQUENTLY ASKED QUESTIONS ABOUT RAINWATER &
GREYWATER HARVESTING

FREQUENTLY ASKED QUESTIONS ABOUT RAINWATER &
GREYWATER HARVESTING

In existing buildings, rainwater harvesting can be relatively inexpensive when capturing rainwater coming from rooftop downspouts into a storage tank to use for irrigation or cooling tower make-up. Consider cooling condensate as another readily accessible source of harvested water in existing buildings. Storage can be handled in either underground or above-ground tanks. Flushing toilets with harvested water creates more issues in existing buildings, as non-potable lines will need to plumbed to each fixture. 

The cost of adding greywater harvesting systems to an existing building is considerably greater than with new construction. Typically, the showers, lavatory sinks and toilets all run to a single line that connects to the sewer system. Harvesting greywater requires a separate line for the showers and lavatory sinks that is run to the collection tank. This extra plumbing is prohibitively expensive to install in an existing building unless the building is being gutted. But every building is different, and greywater harvesting may be practical in some situations.