Commercial (or large residential) rainwater harvesting systems can also supply both potable and non-potable needs. Needs may be different for a commercial building than a residential household. Many commercial or large residential buildings prefer to direct rainwater for toilet flushing, especially in buildings with high customer traffic. The soft rainwater is also beneficial for cleaning purposes as less detergent is needed. Water demand, roof size and available onsite storage should be considered when sizing a collection tank.
Water Savings: Rainwater harvesting can conserve water and reduce your water bill. However, these savings depend on the storage capacity of the system as well as proper use and maintenance.
Reduced Runoff: Diverting a portion of roof rainwater runoff can help reduce flooding and erosion in small streams by reducing runoff volume.
Healthier Landscaping: Rainwater does not contain chlorine or fluoride, both of which can be found in tap water and are not necessary for plant growth.
Commercial and Residential Systems:
All systems require a guttering/conveyance method that drains rooftop runoff to a fine filter, that removes a large percentage of contaminants before the water is stored onsite in an above or below ground tank. A system without a pressure pump relies on gravity feed; therefore, the tank must be located at a higher elevation than the garden and/or building, depending on desired water use. A pressure pump can pump water long distances for outside irrigation and indoor use and does not require the tank to be elevated.