Those in the business of self-sustenance often implement rainwater harvesting. Rainwater collection allows individuals to live off-grid, supplement existing water sources, and much more. For those considering installing rainwater collection systems for rural properties, it’s crucial to establish a plan. Read on for information on rainwater collection systems, how to build them, and details on routine maintenance.

What Is Rainwater Harvesting?

Rainwater harvesting is the act of intercepting precipitation and storing it in a containment unit. It’s then held until needed in future use. Oftentimes, the storage consists of barrels, tanks, or underground cisterns. This collection method uses water that otherwise wastes or runs off to become part of the water table.

Rainwater collection systems are units used to collect potable and non-potable rainwater collection. A compilation of catchments, conveyance, filtration, first-flush, storage tanks, purification, pumps, and other parts, comprise the entirety of the system. These can be later used for various objectives, water classification permitting.

Potable Rainwater Collection: Potable water is that which can be used to drink, cook, bathe, and otherwise use in the home. It’s safe to drink and consume. Approved filtration must be present to purify water before it’s safe for consumption. Examples of purification include UV sterilization, reverse osmosis, and more.

Non-Potable Rainwater Collection: Non-potable water is not cleared for drinking, cooking, bathing, and other sensitive uses. Instead, it can be used for gardening, watering flowers, flushing toilets, watering livestock, and more. Of course, non-potable water can be treated later to convert it to potable.

Why Is Rainwater Collection Important for Rural Properties?

Rainwater collection is important for rural properties for numerous reasons. Clearly, it serves many benefits for those who implement the practice. Sure, it requires a lot of up-front work and materials. The benefits far outweigh the price, though.

First, it can offset failed wells and other traditional means of water collection. Some wells might fail seasonally. Others might fail indefinitely. Either way, water collection systems can serve as backup, or even primary.

Interestingly, because it comes from the atmosphere, it is not a “hard” water, which is the inclusion of minerals, specifically calcium and magnesium. Because of the evaporation and precipitation cycles, and the subsequent manner in which the water is collected (prior to touching the ground), the water has no chance to mix with contaminants.

Rainwater collection also serves well in areas with less annual rainfall. This method serves as an ever-present, opportunistic method of storing rainwater. When it rains, that water is captured and preserved until needed.

This method can also assist in minimizing the localized standing of water around the immediate perimeters of structures. This prevents damage to nearby plants and soil erosion around the foundation. Of course, it doesn’t alter the course of rising waters in times of flooding rains. Think of it as a slight moderator of light to moderate rains rather than a means to mitigate floodwaters.

Perhaps the most important of positives is the off-grid living afforded by rainwater collection systems. This gives individuals the freedom from needing city water piped in from many miles away. It offers a means of independence from basic utilities companies and municipalities. In fact, it's perfect for a Morton cabin in the backcountry.

Of course, proper installation and maintenance of rainwater collection provide potable water for human use. That matters, as humans can go weeks without food but only a few days without hydration. Thus, the ability to procure and store clean water offers massive upside.

In addition to human use, clean water can be used for livestock, gardens, larger crops, and more. It serves as a small-scale, garden-sized agricultural backstop in times of drought.

No matter the use case, rainwater collection systems pay for themselves quickly. It’s much cheaper than trucking in water over long periods of time. For more remote areas, it’s cheaper than installing long water lines from established water mains.

Common Issues with Rainwater Collection

The first-flush valve serves as the initial removal system for bird poop, debris, and other unwanted sediment. Of course, just because the roof appears free of animal feces and other debris, doesn’t mean that it’s clean, let alone sanitized.

If the diverter isn’t large enough, it won’t serve its proper purpose. The first-flush diverter portion of the system must be large enough for the surface area of the water catchment. If it’s too small, it won’t flush enough water, and some of the contaminated water will enter the storage tank.

Even when the system is built proportionally and works accurately, human pathogens can exist on the roof and enter the water supply. Thus, proper filtration and water sanitation must be implemented downstream of the storage area before being used.

Over time, the diverter chamber must be emptied and cleaned. This further minimizes the chances of using contaminated water. To increase safety, routinely test for common pathogens, such as E. coli.

How to Estimate Water Collection Volume

It’s important to know how to estimate your water collection volume. To accomplish this, multiple the catchment area (square feet) by the rainfall total (in inches) by 0.623. (The 0.623 figure converts roof square footage and inches of rain into total gallons of water. As 1 inch of rain over 1 square foot of surface equates 0.623 gallons of water). (Note that roof pitch does not make a difference in water volume collection. It’s the total footprint under the roof – not the square feet of the roof surface itself – that should be figured.)

For example, a 2,500 square foot roof that receives 2 inches of rain produces 3,115 gallons of water. Some of this (3%-10%) will be lost to absorption, evaporation, splashing, runoff, etc. The first-flush diverter will pull some of this water as well. Per this example, expect approximately 3,000 gallons of water from the described setup.

Key Components of Rainwater Collection Systems

There are necessary key components of a rainwater collection system, including the following:

Water Catchments: Generally, roofs serve as the best water catchment. Metal is the preferred material type. Avoid toxic roof styles such as asphalt shingles, lead-based paints, etc.

Water Conveyance: The system must have conveyance that channels water from the catchment. A series of connected rainwater collection gutters, downspouts, and more, carry the water from the catchment to the next phase of the collection system. Cover all gutters with leaf guards to prevent large debris and minimize smaller objects from entering the water supply.

First-Flush Diverter: Of course, dust, dirt, bird droppings, and more, can make it onto the roof (catchment), gutters, etc. Therefore, the first-flush diverter serves as the first level of filtration. It is the first capture method that temporarily holds the initial volume of rainwater. This part of the system separates these undesirable and troublesome elements from the water itself and carries them away.

Water Filtration: After passing through the first-flush diverter, water proceeds through the next level of water filtration. A strainer within a basket catches larger debris. Then, a multi-stage sediment and UV-sterilization filter is needed beyond the tank for improved water treatment.

Water Storage: Commonly referred to as a cistern, water storage is needed as a holding tank. While smaller tanks are common in urban settings (e.g.: 50- to 500-gallon tanks), larger tanks are often used in rural areas (e.g.: 1,000- to 15,000-plus-gallon tanks). Regardless, these tanks should be crafted with approved materials, such as food-grade polyethylene, concrete, galvanized steel, etc.

Water Pumps: Unless gravity is implemented (and even then, it’s often not enough), a water pump is required to send it from the water storage tank to the house, barn, irrigation system, etc. This should be a submersible or external booster pump.

Interested in Building Your Own Rainwater Harvesting System?

For those interested in building your own rainwater harvesting system, it’s important to know just how detailed of a process this can be. Fortunately, Oklahoma State University (OSU) offers a quality blueprint and design for building a rainwater collection system. It’s a highly detailed guide to building a system, with print-friendly PDFs, step-by-step instructions, and much more. It even provides variations in the build, with associated facts and figures, based on the size of the system.

“The catchment area should be calculated based on the footprint created by the roof and not by the square footage of the roof surface,” OSU said. “Be sure to use roof surfaces as near as possible to the planned cistern location, to shorten pipe runs. Because precipitation and water demand (except for in-home demand) are very uneven during the year, the cistern size is based upon monthly average precipitation and demand. These can be obtained by multiplying your average annual precipitation at your location by the percentage of rain during the identified month desired for using the system.”

When considering if rainwater harvesting is right for you, OSU encourages asking yourself the following questions:

●      How will the harvested rainfall be used?

●      How reliable will you need the system to be?

●      What is the size of the catchment area that you have or need?

●      Where is the catchment area located relative to the intended use?

●      What size and type of storage do you have/need to purchase for the harvested rainfall?

Deciding whether a rainwater collection system is right for you, or not, is a personal decision. It certainly offers notable upside with plenty of advantages. Consider it for your rural properties.