Rainwater Harvesting 101: Overview

Rainwater harvesting doesn't have to be hard. By following a few simple steps, you can design a high-quality, low-maintenance rainwater harvesting system for your home or business.

This post will serve as a brief overview of how we at Rainwater Management Solutions design rainwater harvesting systems. As always, we are here to help so if you get stuck along the way, feel free to comment on the post, call us, or email us!

Over the course of the week, we will be posting a few more blog posts going into more detail on each of the steps seen below. So, let's get started!


The core of how RMS approaches system design is the WISY 4-Step System. This 4-Step System greatly improves the quality of the rainwater and is designed to continue reducing the amount of sediment in the water as it is taken into end use. In addition to the 4-Step System, we size tanks to ensure overflow and make sure that they fit the project's needs. Pump and post-tank filtration are then the final steps to a complete system!

When researching and designing a rainwater harvesting system, it is important to consider the factors of:

  • What will I use the water for? 
  • How much water can I collect?
  • What is the impact of my project?
  • Where will I place my storage tanks?
  • Are there local/state restrictions on rainwater harvesting? What permits do I need?
  • What is my budget?

Of course there are more items to consider, but these are the common ones that come into play.

Pre-filtration is key to creating a high quality of water in your tank. Rainwater by itself is very clean water, but collection from roof areas introduces pollutants/contaminants in the form of debris from leaves, sticks, rocks, or anything that may wind up on the roof. Reducing particulate is important for several reasons, but most importantly it removes larger particulate that may carry pathogens as well as causes cloudiness in the water.

Reducing particulate is important for several reasons, but most importantly it removes larger particulate that may carry pathogens as well as causes cloudiness in the water. WISY pre-filters work by removing larger particles of debris (as small as 0.011" in size) and drawing clean water through the filter screen to send it to the tank. This means that only very small particles make it to the tank after the pre-tank filter. With proper pre-filtration you can have cleaner water and you should not have to clean your tank out. 


Smoothing Inlets are designed to direct the water upwards upon entrance to the tank. This prevents disturbing the healthy "bio-film" that has settled at the bottom of the tank. The rush of water directly into the bottom of a tank without a smoothing inlet would stir up fine sediment (think of quickly pouring water into a fish bowl) that could then be drawn in by the pump. The "bio-film" at the bottom of the tank actually works to eat any bad bacteria that may enter the tank and help create a healthy water environment.


The third step in the WISY 4-Step System is the floating filter, which draws water in to the pump from below the surface level to avoiding taking in any small particulate that may be floating.

This step reduces the amount of particulate that goes to end use which can promote the longevity of the pumps, post-tank filtration components, and reduce build-up in piping (or drip-emitters in irrigation systems).


Tank overflow is essential for a healthy water environment. The WISY overflow devices will siphon small, floating particulate off the surface of the water, while also providing a path for excess incoming rainwater to overflow to. These overflow devices also protect backflow from storm drains.


So there you have it! Four simple steps that help create a very high-quality rainwater harvesting system for your application. In the next few days we will have more posts going into some more detail on each of these steps, explaining the importance of these steps and how to properly size them so stay tuned!

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