Harvesting Rainwater

Rainwater is a free resource and it is collected by many homeowners across America. Those of us who decide to harvest rainwater can gain thousands of gallons of free water with a little effort and just a few dollars.

One of the best sources to collect rainwater is your roof. When rainwater falls onto the roof, it rolls down the sides of the roof and into the gutter and spout system. Instead of allowing that water to fall through the gutter and spout, onto the ground where it is eventually absorbed in the ground, catch the rain and save it!

The most basic way to save rainwater is with some tubing and an old barrel. Of course, catching rainwater can be much more elaborate but the simplest system involves a pipe and a storage vessel of some type. The photo below shows a very basic set up and was our first rainwater “system.” This rainwater catchment system was a pipe straight from the gutter off the roof into a rainwater barrel:


Living in the country, we are on a well. Although our water is free, we must use an electric pump to supply our home with our well-water. We have always been careful with our water usage, despite having natural springs and a stream on our property.

During summer months, we are vigilant with our well-water usage — especially during hot, dry spells. Having a quantity of usable rainwater at our disposal is very handy during these times. Not only does the harvested rainwater provide all of the water for our garden irrigation, but having an ample supply of rainwater also helps to provide our property with a passive hydration system in and around our living quarters. And if, for some reason, we were forced into a grid-down situation, our collected rainwater could be used for a variety of household water needs.

Collecting rainwater is a very simple process, but be forewarned: Rainwater is usable water for irrigation purposes only. Rainwater collected from a rooftop is not potable water, as it contains minute contaminants from the collection system. We do not drink this water, nor would we recommend you try it either — unless it was a life-or-death situation and the rainwater was filtered, and then boiled (possibly even treated). We also do not recommend that you use rooftop rainwater for your livestock, but again, if faced with a life-or-death situation, collected rainwater could be filtered and sanitized for use.

Rainwater Catchment Systems

Simple rain barrels made of recycled food-grade plastic or polyethylene can store between 50-55 gallons of water each. Buying a rain barrel costs about $50-$100, but a recycled food-grade rain barrel is an inexpensive purchase. Sometimes food-grade barrels are offered for free.

To harvest rainwater, cut a hole in the top of your rain barrel, then situate the barrel at the base of the roof downspout. Depending upon the length of your downspout, you may need to remove a section of the downspout. If you have a downspout on each corner of the roof/house, place a rain barrel under each. This is the most basic rainwater catching system that any homeowner can accomplish with little cost and effort. Our original rainwater catchment system looked like this:


Sophisticated catchment systems have gutter pipe-connected rain barrels (a barrel system) or a very large cistern-style water tank to hold much larger quantities of rainwater. The large cisterns are often above-ground and can hold from 500 gallons to thousands of gallons of water. Some of these large cisterns can even be buried underground.

Our total rainwater catchment system is for 1,500 gallons of rainwater. Our system includes an installed livestock tank that holds 1,100 gallons and this photo shows the tank shortly after we installed it. Prior to installation, we prepared the base area with sand, then leveled it. And since the tank is unsightly, it’s now hidden from view with a tall fence.

The stored rainwater can be used by attaching a hose to the tank’s base using a shut-off valve that we installed. When we need to use the rainwater for our garden, we open the valve and water is gravity-fed via an attached garden hose. We keep rainwater throughout the Winter season so we insulate the bottom valve to prevent freezing.

With a small rainwater system, an inexpensive underwater bilge pump can be added, too. Although many pumps are electrically-dependent, they offer a means to pump water out of the rainwater system. An underwater pump is required if there is a problem with gravity-fed water release, so keep this in mind if you are interested in collecting rainwater for garden use.

Our old rainwater collection system began as a system of several recycled food-grade barrels. As our water needs increased, we added to our barrel system,  connecting the barrels with PVC piping. Using a submersible pump, we were able to harvest our rainwater for our gardens.


Determining the potential rainwater harvest, compute the following:

With 1-inch of rainfall, the yield is approximately 600 gallons of rainwater for every 1,000 square foot of the collection area.

An average home of 1,500 square feet of roof, using rain barrels at each corner downspout, has the ability to collect 900 gallons of rainwater per inch of rainfall. To determine the yearly rainwater yield, multiply the 900 gallons by the average rainfall in your region. Isn’t that an incredible harvest?

Now what’s stopping you from collecting some of your own rainwater for your own gardens?

14 thoughts on “Harvesting Rainwater

  1. Can you believe there are some states/jurisdictions where it is *illegal* to collect rainwater? What will they come up w/next? Taxing air?

    I installed my first barrel this spring (attached to my downspout like your original system). We’ve had so much rain this year that I haven’t had to touch our Town water for the garden. Maybe it’s my imagination, but I think the plants are doing better w/”natural” water. ;)

    • Shire girl, I hate to say it but wasn’t there some type of proposed EPA regulation that was going to limit carbon dioxide but people argued that it was part of a mammal’s respiratory system? lol

      Making rainwater collection illegal is as crazy as the State of Maryland taxing residents for having concrete or blacktop on their property. Evidently, having a hard, nonporous surface like a sidewalk, patio, or driveway hurts the Chesapeake Bay with the lack of proper runoff. (Why didn’t the city/state planners think of this before they paved Maryland up everywhere?)

      Glad to hear that you’ve started harvesting rainwater. And yes, rainwater is “soft” water and has a very low mineral content == rainwater is beneficial to plants!

      • Funny you mention that – m y folks live in “the People’s Republic of Maryland” (northern HoCo) and are livid about this. I don’t understand how people can be taxed on sidewalks that were installed by the municipalities! That makes no sense. Just one more reason for them to move to VA.

        Love your blog! Have learned a TON from you already. And I love showing your little goats to my kids (haha, no pun intended). Adorable!

        • Shire girl, I grew up in Montgomery County and lived there until we moved here in 1987. Both of us have family in MD and the comments about ever-increasing taxes and regulatory nonsense is never-ending. We don’t miss MD at all! Unfortunately, some of the ‘go green’ regulations have come into parts of Virginia. Things like LEEDS-certified building and pervious concrete are being utilized without fully understanding what is involved.

    • Harvesting rainwater is unlawful for most persons/places in the Republik of Kolorado :-( due to the seemingly “unique” water rights statutes. I’m not taking it, I’m simply repositioning the point of use – it will still go to land with some beneficial use before it evaporates or soaks into the ground. Regulations be damned – gutters and downspouts are now installed and the barrel is dry and ready.

      • Hi Wild Bill. I thought Kolorado was one of the states where you become a criminal for having rain barrels. Sheesh…..

        It does my heart good to hear your plans and your stance. It’s time We The People take a strong stance on the tyrannical government — Not One More Inch!

  2. Take it a step further and set up your rain collection system on an automated drip irrigation system. No manual watering necessary as long as you get a couple of inches of water per year and are able to collect a lot.

    • Jonathan, You’re so right, and we’ve talked about an irrigation system. Of course, we haven’t done anything about it at all. So every time I stand with a hose in my hand for 30 minutes or more, I remind myself that we still don’t have any type of drip system in the ground. Some day……. :-)

    • Jonathan, How far can a drip system be installed away from the rain collection system? My garden is about 400 yards away from my house and I’m not sure how I would get the water from the collection barrels to the drip hoses in the garden. Would installing a PVC conduit at maybe 2-3% grade work?

  3. Pingback: Got Water? « Wood Ridge Homestead

  4. Great article. We have been thinking about adding a rain barrel system for years and we are hoping to do it next spring. We will just start out simply as you did and use it to supplement the water in our garden.

    Shire Girl is right, in many areas collecting rain water without owning a water share is illegal. Hard to believe! It was in our area until just recently. A local car dealer set up a water collection system to use to wash the cars on their lot and then they were cited for not having a water share. This caused quite an uproar and the law was changed to allow home owners and others to collect water.

    • Greetings, S! Good to hear that you’re going to begin collecting rain water. Yes, Shire Girl is correct and I think it’s crazy to outlaw rainwater collection. People have been instructed to conserve water, then when they do, they are fined. Crazy!

    • @S – if you’re thinking of buying off-the-shelf components, the least expensive barrels I found during my internet searching are @ hayneedle.com with different style, sizes, colors, etc. I got a flat-back model to fit tight against the cabin as it sits on the deck.

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