Rainwater Harvesting

What is it?

Rooftop rainwater harvesting is the collection, conveyance, storage, and distribution of natural rainwater for non-potable applications。 Instead of storm water immediately running from roofs into sewers, it gets collected and stored for later use, such as:

  • Landscape irrigation
  • Fire suppression
  • Toilet flushing
  • Industrial processing
  • Vehicle washing
  • Building washing/power washing
  • Cooling towers
  • Pool/pond filling
  • Laundry washing
  • Household cleaning

Rainwater harvesting is ideal for large commercial and industrial buildings, especially ones with expansive parking lots, and can be retro-fitted to existing buildings or integrated into new building designs。 Not only does the facility save water consumption costs, but it also reduces stormwater runoff on the site。

Pfister Energy can design a system to meet your facility’s needs, depending upon roof size, water demand and your intended usage.

Why should you harvest rainwater?

Rainwater is renewable, sustainable and a high quality water source. The benefits of collecting rainwater include:

  • Flood and erosion reduction – redirect storm water runoff
  • Demand and utility bill reduction – use rainwater for flushing toilets and irrigation
  • Improve your landscape – use rainwater, it is free from pollutants, salts, minerals, and other natural and man-made contaminants

No matter what the particular application, the core components of a typical rainwater recovery solution are the same. 

  • Collection – comprised of the catchment area (i.e., roof) and conveyance system (i.e., gutters and downpipes)
  • Holding Vessels – cisterns, tanks or other suitable storage container
  • Roof-wash system (optional) – usually the first 10-20 gallons of rain are diverted from the cistern to improve water quality and minimize debris build-up
  • Delivery System – the delivery system consists of pumps and piping (e.g., water is withdrawn from the holding vessel by a pump that delivers the water to sprinkler heads for irrigation)
  • Filtration (optional) – to remove particulate and contaminants for the downstream application. This can be simple or complex, depending on the requirements and applicable health and environmental regulations

*Rainwater may be contaminated by pollutants, therefore it is often not considered suitable for drinking without treatment。