Benefits of Rainwater Harvesting for Commercial Buildings

March 27, 2013 at 4:14 pm
Rainwater Harvesting
Example of a commercial rainwater harvesting system

Office buildings, shopping centers, apartment buildings, and other commercial properties can reap substantial benefits from rainwater harvesting. Whatever the motive – sustainability, reduced utility costs, or improved landscaping – rainwater harvesting makes great sense for commercial property managers.

Throughout the U.S., ground water resources have been declining and the cost of water is on the rise. Drought has become the continuing climate in many parts of the U.S. and commercial property has taken a significant financial hit as a result. Given these circumstances, the capture and recycling of rainwater suddenly makes sense:

  • Unlike groundwater, rainwater is not hard. Without chemicals and minerals, it can prevent corrosion and scale on equipment and re-distribution systems.
  • Captured water is free for the taking and delivery.
  • Landscaping loves rainwater, free of salts and acids.
  • Harvesting reduces run-off and its consequent harmful impacts.
  • Collection and reuse eliminates periodic demand stress on public water sources.
  • Using harvested rainwater can reduce water bills in some areas and may be eligible for tax incentives.

Some 99% of the water used at a commercial site is not for drinking. It flushes toilets, runs showers, and cleans. Collecting rainwater provides a new resource, a clean source of water for landscape irrigation. The salt-free water will seep deep into the soil where it will reduce the salt accumulation that is harmful to root growth.

Picture the simple process at a single home. The rain rolls off the roof into gutters that channel it into barrels or tanks. It is, then, distributed simply by bucket or hose to landscaped areas. Systems become more complex with the size of the home and the intended use, but in most simple assemblies, the system relies on gravity and the weather.

The components are the same for commercial property: large buildings, tall ones, apartment houses, and shopping centers – anywhere there is significant roof exposure. Consequently, most rainwater harvesting systems are custom engineered to the building and its landscaping plan. The development of an appropriate commercial rainwater harvesting plan involves three phases:

  • Site engineering: Draw the natural drainage paths, their highs and lows. Identify natural catchment areas, and determine how planned landscaping will alter the terrain and flow. Design the means to move the water from catch areas to planting, for example, through gravity or pump pressure.
  • Demand calculation: Measure the landscaping needs. Thirsty plants need more water over time.  Rainwater is not dependable, so it is important to know how much you can rely on the catchment and on the utility water supply.
  • Construction: Design and implementation of a new construction is easier than adapting an existing site. An existing site needs retrofitting, but new sites can match plant placement and thirst to the collection and distribution system.

If you are interested in exploring whether a rainwater harvesting system would make sense for your commercial building, make sure to work with a landscape contractor who has planning, architectural, and engineering experience. Choose one that you can form a working partnership with. Review current and completed projects that resemble your size and plan. Review the numbers carefully, and see if there are tax incentives. You’ll love the outcomes!

[Image credit]