Beginner’s Guide to Rainwater Harvesting

Have you ever stood in the middle of a rainstorm, soaking wet, and thought about the sheer volume of water pouring down from the sky? It’s an awe-inspiring experience, one that has pushed me to explore the incredible practice of rainwater harvesting.

Did you know one inch of rain falling on a 1,000-sq.-ft. roof can yield approximately 600 gallons of water? That’s enough to fill 10 bathtubs! And you can harness this water for your garden, for flushing the toilet, and many other practical purposes. Let’s explore.

What Is Rainwater Harvesting?

Rainwater harvesting is the practice of collecting and storing rainwater for later use, typically from rooftops via gutters and pipes into a storage tank. It dates back thousands of years.

Evidence of rainwater harvesting can be found in ancient civilizations, including the Indus Valley on the Indian sub-continent, as well as Rome and China. Today, this old-world wisdom is experiencing a resurgence, with more people recognizing its benefits in an increasingly water-stressed world.

Benefits of Rainwater Harvesting

Rainwater harvesting offers a myriad of advantages, making it an attractive option for homeowners and eco-enthusiasts alike.

My rainwater harvesting system connects to my drip irrigation system to keep my plants happily hydrated. But with the right filtration system, you also can use it for livestock watering, emergency preparedness, cooking, flushing the toilet and even drinking.

• Water conservation: Rainwater harvesting reduces the strain on the municipal water supply, making it a sustainable alternative, especially in areas experiencing water scarcity.
• Reduced water bills: By utilizing harvested rainwater for non-potable uses like gardening, flushing toilets and laundry, households can significantly cut down on their water bills.
• Improved plant health: Rainwater is free from many chemicals found in tap water, like chlorine, which can be harmful to plants. Using rainwater for irrigation results in healthier, more vibrant gardens.
• Emergency water supply: In cases of emergencies or disruptions to the municipal water supply, a rainwater harvesting system can serve as a valuable backup resource.

While rainwater harvesting is largely beneficial, potential challenges should not be overlooked.

The initial setup cost can be high, and the system requires regular maintenance to ensure clean and safe water. Also, while harvested rainwater is great for many uses, it’s not immediately safe for drinking unless properly treated.

Is Rainwater Harvesting Legal?

In the United States, generally yes, but regulations vary by state. Some states, like Texas and Virginia, encourage rainwater harvesting with tax incentives. Others, like Colorado, have specific laws restricting the practice due to water rights issues.

Internationally, rainwater harvesting is legal and practiced in many parts of the world, but local regulations can vary. Always check with your local municipality before setting up a system.

What To Consider Before Harvesting Rainwater

Embarking on a rainwater harvesting venture is exciting, but it’s not without its challenges. Here are some things to consider:

• Initial investment: It can require a significant upfront investment, depending on the complexity of the system.
• Maintenance: Regular cleaning of gutters, filters and tanks is essential to prevent contamination.
• Space: You’ll need sufficient space for the storage tank, which can be bulky.
• Water treatment: If you intend to use harvested water for drinking or cooking, consider the cost and process of treatment.

Ways to Harvest Rainwater

If you’re a DIY enthusiast, setting up a rainwater harvesting system can be a rewarding project. Here are some methods to consider:

• Rooftop rainwater harvesting: The most common method. Rainwater is collected from the roof and directed into a storage tank via gutters and downspouts.
• Rain barrels: This is the simplest and most cost-effective way. Rain barrels collect water directly from your downspouts. They’re ideal for gardeners.
• Rainwater tanks/cisterns: These larger systems can store a significant amount of rainwater for household use. They’re more expensive than rain barrels but provide a substantial water source.
• Rain gardens: These designed landscapes use plants and soil to capture, absorb and clean stormwater runoff.
• Underground storage tanks: These are large containers buried underground to collect and store rainwater. They’re often used in commercial settings or places with high water demand.
• Dry system: A variant of the above, the dry system includes gutters that direct water to the storage tanks, but the pipes dry out between rainstorms.
• Wet system: Here, the collection pipes are always filled with water. The storage tank can be located away from the collection surface, even underground.

After Harvesting: Water Purification and Use

Once you’ve collected the rainwater, it’s time to put it to use.

For gardening, irrigation or toilet flushing, no purification is necessary. Bear in mind that untreated rainwater, even if it looks clean, is not safe to drink or cook with. Rainwater can contain various types of bacteria, viruses, algae, parasites and fungi that can cause health issues. It might also contain pollutants or debris from the atmosphere or the surfaces it came in contact with.

Water purification

There are several ways to purify rainwater, and the best method largely depends on the quality of the collected water and its intended use.

Every system, even if it’s just rain barrels for the garden, should include gutter guards or downspout screens to stop debris from getting in there and clogging things up. This is an essential pre-storage treatment. Then, for after-storage treatment, you can use the following:

1. Boiling: This kills many types of disease-causing organisms. However, it won’t remove chemical contaminants.
2. Filtration: Water filters vary, from simple cloth products eliminate small particles to more complex ceramic or carbon filters to remove chemical pollutants. Filters can remove many types of contaminants, including some chemicals. But they might not remove all types of bacteria or viruses.
3. Chemical treatment: This usually involves adding substances like chlorine or iodine to the water, which kill bacteria and viruses. However, they may not be as effective against some types of parasites, and may give the water a noticeable taste.
4. UV treatment: Ultraviolet light can kill bacteria and viruses in water. UV treatment systems are often used in homes with private wells or other non-public water sources.
5. Distillation: This involves boiling the water, then condensing the steam back into liquid. This method can remove most contaminants, including bacteria, viruses and chemicals.