The practice of harvesting rainwater dates back centuries and is still the most common type of water harvesting system. Wahaso specializes in designing and building rainwater harvesting systems for large-scale applications. Unlike the simple systems installed by other rainwater harvesting companies for homeowners, our rooftop rainwater harvesting systems are designed with the commercial-grade components and sophisticated controls required in commercial buildings for reliability, automated functions and connectivity to BAS systems. The Wahaso commercial rainwater harvesting systems produce treated water that is safe and suitable for non-potable applications such as toilet flushing, irrigation and cooling tower make-up.

Rainwater Harvesting System- WAHASO

Water Harvesting System Design

Wahaso commercial rainwater collection system is designed to meet rigorous commercial building and regulatory requirements. The first step in any rainwater harvesting system is pre-filtration upstream of the cistern. This helps to keep the cistern clean and reduce the load on downstream processing equipment. Wahaso rainwater harvesting for commercial buildings uses a variety of pre-filters including hydraulic jump cascade filters, NSBB units, vortex filters, downspout filters and more.


After pre-filtration, the harvested water is stored in a cistern rainwater harvesting storage. (See Storage for more information.) The Wahaso system includes transfer pumps that convey the water from the cistern rainwater harvesting storage to a skidded processing system where it is filtered and sanitized for reuse. Wahaso uses Ultraviolet (UV) sanitation in our rooftop rainwater harvesting systems, which kills pathogens and bacteria that can present a health risk. Chlorine can also be used for applications such as toilet flushing, where residual sanitation is required.


Treated water is delivered to the end use via Wahaso booster pumps. These rain water harvesting pumps include Variable Frequency Drives (VFDs) and integrated into the Wahaso Control System. Wahaso employs custom-programmable logic controllers that not only manage the pressurization functions, but also monitor tank levels, differential pressure on filters, UV function and chlorine levels. Our control packages are capable of interfacing with the Building Automation System (BAS) and logging critical data.


Best Rated Rainwater Harvesting Systems

Best Rated Rainwater Harvesting Systems

System Benefits

  • The Right Size for the Job. Wahaso’s proprietary pre-design analysis helps to determine the proper size for any rainwater system. A system that is too large is not cost-effective, but under sizing a system can lead to lost potential.
  • Low Maintenance. The Wahaso system has been designed for minimal maintenance with few consumables.
  • Integrated System Design. Wahaso’s greywater processing skids are pre-assembled and integrated into comprehensive system designs that include all pumps, storage, filtration, sanitation and controls.
  • Robust Controls. Wahaso’s proprietary control system is custom programmed to monitor and track all system activity.

Standard Systems

Wahaso offers both standardized and custom rainwater harvesting systems. Our standard systems are designed for both small and medium-sized projects and incorporate filtration, sanitation and tank sizing. If our standard systems do not fit the project, Wahaso will work with architects and engineers to design a custom system. For more information on our standard rainwater harvesting systems, download the information sheets.

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