What is rainwater harvesting?

Rainwater harvesting is the capture and storage of rainwater for detention or future use.


How much water can I capture off of a roof surface?

One inch of rain on a 1,000 sq. ft. roof surface yields 620 gallons of rainwater.

In order to determine how many gallons you can collect off of your catchment surface annually; take the  roof footprint and times it by .623 and then times by the average annual rainfall in your area.

Catchment surface x  .623  x  average annual rainfall = Total rain catchment.


What are the benefits of harvesting rainwater for a homeowner?

  • Stormwater Control – MS4 Compliance
  • Reduced cost of site plan
  • Mitigation credits
  • Reduced cost of irrigation
  • Availability of water
  • Reduced Cost of water
  • Superior water quality (Naturally soft!)


What are the advantages of using rainwater harvesting to help mitigate runoff?

Using rainwater harvesting as a method for stormwater mitigation gives you more than just a solution for your stormwater problem, it provides you with a resource, an asset, to be used!

Rather than taking rainwater and paying to direct it offsite in a controlled manner just to turn around and pay to bring water back to your site for use, you can easily integrate a rainwater harvesting system to capture the rainwater and filter it for use. This solution will solve your stormwater runoff problem and save you money on municipal water costs.

Rainwater Resources™ will help you optimize a rainwater harvesting system to maximize runoff reduction.


What can harvested rainwater be used for?

Harvested rainwater can be used in the same way any water is used; Irrigation, Indoor potable use, commercial or industrial processes, flushing toilets, for laundering, agriculture use, fire protection, washing your vehicle fleet, cooling tower make-up water, etc..

Rainwater is naturally soft water so it offers numerous cost-saving benefits wherever it is used.


What happens during a drought period?

Rainwater is used in hundreds of homes throughout the United States as a sole source of water. However, most applications are installed to include a backup source of water such as a well or municipal water supply.


Is rainwater safe to drink?

When rainwater falls from the sky it has just gone through nature’s great distiller. Stage 1, Evaporation: when water is drawn up into the sky as vapor. Stage 2, Condensation: when the vapor condenses into water droplets. Stage 3, Precipitation: when water falls to the ground. Theoretically this water is at the highest level of purity that could be desired for human consumption.

Although pockets exist in the northwestern part of North America where rainwater can become quite acidic, in most areas across the United States water falling from the sky is of exceptionally high quality for drinking. Due to EPA’s control on scrubbers and other methods most rainwater absorbs very little atmospheric contaminants as it falls from the sky. With appropriate pre-filtration, and adherence to BMP’s for filtration and purification, rainwater is not only safe to drink, but is an exceptionally high quality drinking water.

In many jurisdictions across the United States, including the city of Atlanta, rainwater is approved for potable water use in residential applications with proper filtration and purification. Due to the EPA mandate to monitor and report water quality, as it applies to municipal water suppliers, most jurisdictions have not approved rainwater for public use drinking water. Federal, state and local codes will determine when and where rainwater can be used as potable water.


How much water should I store?

Storage capacity is determined by carefully analyzing supply (catchment area), demand (how you plan to use the water), overall water management goals, and project budget. Storage becomes the equilibrium of supply and demand. Rainwater Resources™ has numerous tank options to customize the exact tank preferred for each application to make sure that the system is properly balanced and will offer longer term success.


Can a system be installed on an existing home or building or does it need to be new construction?

A rainwater harvesting system can be retro-fitted into an existing building depending on the layout of the building and the type of system to be integrated.

However, integration during construction usually allows for more options and a more seamless application.


Does rainwater harvesting provide any LEED points?

Our engineered rainwater harvesting systems have the ability to provide up to 12 LEED points for a USGBC LEED Certified project.

SS Credit 6.1 – Stormwater Quantity Control, 1 Point

SS Credit 6.2 – Stormwater Quality Control, 1 Point

WE Credit 1 – Water Efficient Landscaping, 2-4 Points

WE Credit 2 – Innovative Wastewater Technologies, 2 Points

WE Credit 3 – Water Efficiency, 2-4 Points

MR Credit 4 – Recycled Content, 1-2 Points


Why should I be interested in rainwater harvesting when there is so much water already available for my use?

It is a fallacy that there is an over-abundance of water available for our use in the states. The population of the United States is expected to double over the next 50 years and existing surface water and groundwater resources are being depleted. Already, there are places in the USA that are experiencing shortages because demands are greater than available supplies. Rainwater harvesting provides us an opportunity to conserve and extend our existing resources.


Does this system require maintenance?

Part of the beauty of our system design is the very little ongoing maintenance that is required. Rainwater Resources™ recommends a bi-annual cleaning of the filter insert, and an annual maintenance on the filtration and purification equipment.

When your system is due for maintenance, you will be automatically contacted to schedule an appointment for one of our certified technicians to complete the maintenance.



Expert opinions, technical briefings and other information


Informative videos regarding rainwater harvesting


Frequently asked questions on rainwater harvesting


Resources for rainwater harvesting & sustainable design


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