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How to Harvest Rainwater In Your Garden

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Rain Barrel

A swift and dangerous storm blew through my neighborhood, knocking down trees and taking down power lines. It was nearly a week before power was restored to a good portion of the town. Unfortunately, my pleas to the power company went unheeded; we were simply last in line for repairs. And being without power meant our well pump wouldn’t run, so our water supply was gone. We were prepared, though, and have a quality hand well pump and also had a source of rainwater that we could use to flush toilets and provide water for the garden, goats, and chickens. You can harvest rainwater in your garden, too, if you know how. 

You can harvest rainwater in your garden by using rain barrels under your downspouts, garden swales or ditches, and even manufactured ponds and reservoirs. You can then use the water to irrigate your garden, water your livestock, or provide water for your family once it is properly filtered. 

In this article, we’ll talk about several methods to catch and harvest rainwater from your garden or home. Harvesting rainwater can be as simple as setting out extra buckets when it rains or building a more extensive system. Before we do that, though, we’ll look at whether or not harvesting rainwater is legal and why you should harvest rainwater from your own garden. 

Why You Should Harvest Rainwater in Your Garden 

If you depend on your garden to feed your family, you’re going to need to keep it well-watered even if rainfall is not plentiful. If your home uses public water, watering your garden can be costly and sometimes illegal. 

On the other hand, if your home uses a well, you need to watch your water supply, so you don’t run your well dry by irrigating your garden with it. Droughts, water main breaks, and power outages can also cause disruptions in the water supply that might make it difficult to water your garden. There are a number of ways to harvest rainwater in your garden so you can always keep your garden growing and healthy. 

The Legality of Harvesting Rainwater from Your Home and Garden 

Before doing anything else, make sure it is legal to harvest rainwater from your garden. Unfortunately, in some areas, this is illegal. Avoid hefty fines and legal fees by checking with your local government first to see if it is legal and if you need a permit. This article will give you a quick rundown of some of the states that have water collection laws in place, but make sure you do your own research. 

Once you are sure that harvesting rainwater is legal where you live, you can figure out which method is best for your situation. 

Collecting Rainwater in Buckets 

In this video below the guy shows his DIY 5 gallon bucket rain collection system!

YouTube video

Collecting extra rainwater in your garden can be as small and simple as sitting out some extra buckets when it rains. A few buckets will give you a little extra water for your container garden or potted tomatoes, but it won’t get you enough to irrigate a large garden, of course. Keep in mind that open buckets can be hazardous to small children. They can also be a breeding ground for mosquitos, so don’t plan on keeping buckets of water around for a significant amount of time. 

Although setting out buckets is easy and convenient there are other methods that you can employ on a larger scale if you choose. 

Collecting Rainwater from Your Home or Shed Roof 

Roof Rain Water Collection

A very easy way to collect rainwater for your garden is to use a commercially made rain barrel. These rain barrels are closed systems to prevent small children or animals from accidentally falling in and drowning. 

A large barrel has a mesh screen on top and a faucet at the bottom. You simply place the barrel underneath a downspout so that water can flow through the mesh screen and fill up the barrel. When the tap is closed, the barrel fills up. To use the water, you can attach a hose to the faucet. When you open the faucet, the water flows into the hose, and you can use it to water your garden. 

You can also attach the tap on you rain barrel to a soaker hose, which will spread the water out throughout your garden. Rain barrel taps may run slowly. You can raise your barrels up on cinder blocks or place them at a higher elevation than your garden to help the water run more quickly. 

Rain barrels come in various shapes and sizes, so you can find one that fits your needs and your décor. You can put a barrel underneath each downspout if you like. 

DIY Rain Barrel for Rainwater Collection

If you don’t want to purchase a rain barrel, you can use a spare trash can or a galvanized stock tank. This website gives you a tutorial on how to DIY your own rain barrel from inexpensive parts.

If you don’t have a shed or roof near your garden, though, you might want to use your polytunnel as a rain catchment system. 

Collecting Rainwater from Your Polytunnel

If you have a polytunnel or DIY hoop house in your garden, you can use that to collect and harvest rainwater. The easiest method to collect rainwater from your polytunnel is to purchase adhesive gutters. 

These lightweight, flexible gutters will attach to the outside of your tunnel and somewhat parallel to the ground. The idea is similar to the gutter you would find on the roof of your house. You’ll angle the gutters slightly down towards the direction of your barrel, tank, or pond. 

Allow a foot or two of the gutter to stick out from the side of your tunnel. Then angle the gutter to drain into a barrel or pond to collect the water. 

Polytunnel gutters are a quick and easy solution for catching rainwater in your garden and it doesn’t take much time or effort to set them up. However, if you are looking for water collection on a larger scale, you might be interested in digging swales. 

Digging Swales to Collect and Harvest Rainwater

If you tend to have a lot of runoff during rainstorms, you can dig swales to direct the water to a reservoir or pond to hold it until you need it or move it through the garden. A swale is really just a lengthy ditch that is sloped. The ditch will slow down the rate of runoff and send it wherever you might want it to go. 

Digging swales can be backbreaking and time-consuming, but they do come in handy to protect your garden from runoff and store the water for future use. In this video, great Escape Farms demonstrates how to dig a swale and how well it works in the rain. You can dig your swale by hand, but you might be better off using a plow or excavator.

You can also dig your swales so that they will irrigate your garden over the course of several days as the water slowly flows and seeps into the ground. Or, you can use the swales to send water to an underground tank or pond which will capture the water until you are ready to use it.

Creating a Pond or Reservoir to Collect and Harvest Rainwater

Rain Water Pond

Another way to harvest rainwater from your garden is to create a pond or reservoir to collect and store rainwater. For example, you may want to use a garden pond in concert with a swale or rain gutter. 

To create your own pond, you can purchase ready-made hard plastic pond liners from big box stores, or you can even create your own.

How to Dig Your Rainwater Pond

To make your own pond, you’ll want to clear away any vegetation from the area where you would like your pond to be. Mark off the outside of the pond with pegs or twine. Next, you’ll dig out the pond to whatever depth you like. The bigger the pond, the more water it will hold. Again, you could do this by hand but you might be better off digging your pond with an excavator, depending on the size and depth you choose. 

Lining Your Rainwater Pond

You’ll need to line the pond to keep the water from draining out. PVC and rubber are popular liner materials, and you’ll need to make sure the liner is big enough to fully line the pond as well as hang over the top to create an edge. Nualgi Ponds has a calculator on their site to help you choose what size liner you need for your pond. 

Using Water from Your Rainwater Pond

You may need to create swales or rain gutters to direct water to your pond. You can also add pond plants and even some types of fish to create a beautiful yet functional rainwater pond. You can use the water in the pond by filling buckets by hand or even purchasing a small pump to pump water through a hose to the area you need it. For best results, though, you’ll want to keep your pond as close to the garden as possible. 

Keep in mind that you might need a permit or fence before you can legally dig your pond. 

Harvesting rainwater from your garden doesn’t need to be fancy or expensive. And while you can purchase extensive underground systems, you may only need a few barrels or a small pond to meet your own personal needs and budget. Make sure to follow safety precautions, government restrictions, and avoid these common mistakes

Not only is rainwater a free water source, it is a great resource for a backup system for your own water needs. 

Related Questions

Can I use open barrels for rainwater collection? 

Technically, yes, you can use open barrels. However, you need to consider the dangers of small children falling into the barrels. Another problem with open barrels or buckets is mosquitoes. Mosquitoes will breed in open containers of water, so you’ll either need to cover them with screening or include fish that will eat mosquito larvae. 

Is rainwater safe to drink? 

When you collect rainwater, you’ll need to filter it before you can drink it. You may want to pretreat your rainwater with chlorine before running it through a Big Berkey filter to ensure your water is safe and clean. 

Is rainwater the same as greywater? 

Rainwater is rain that has been collected for watering gardens or livestock or other uses. Greywater is the wastewater that comes from showering, washing dishes, or washing clothes. Greywater can be used to water your yard, flower gardens, and non-root crops. 

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Hi! I’m David. For most of my life I have been interested in emergency preparedness. Over the many years things have changed a great deal. From freeze dried food, to LED lanterns, preparing for an emergency has never been easier. The continual research I have done over the years has become the basis for this website. Now it is one of the most trusted sources to learn about emergency preparedness.