Environmental Benefits of Rainwater Harvesting + Free Webinar

Enjoy a free webinar on this topic!

Learn the whats, whys and hows of rainwater harvesting with BlueBarrel's founder, Jesse Savou.

(To contextualize the intro, this webinar was given live on April 21st, 2020, the eve of Earth Day's 50th anniversary, and the onset of the global coronavirus pandemic.) Click the image to play recording:

Environmental Benefits of Rainwater Harvesting in Brief

April is Earth Month. What if you could make a big difference just by installing a few rain barrels?

You've heard rainwater harvesting is good for the environment, but if you're like most of us, you can't explain exactly why.

Here are a few quick points followed by some key details for why rainwater harvesting is absolutely vital for a thriving ecology, both in your own garden, and for the global water cycle!


Rainwater harvesting is a great way to:

Environmental Benefits of Rainwater Harvesting

  • Protect your local watershed;
  • Make your garden more resilient in the face of droughts, floods, and fire;
  • Restore the hydrologic cycle;
  • Recharge groundwater;
  • Reduce your carbon footprint;
  • Maintain healthy soils;
  • Keep your garden lush and healthy (which, in-turn, enriches habitat and helps to regulate local temperatures and precipitation);
  • Lessen the impacts of extreme wet and dry spells;
  • Mitigate impacts of climate change;
  • Utilize recycled materials (a given, if you choose BlueBarrel!)

Environmental Benefits of Rainwater Harvesting Explained

Most of us know that rainwater harvesting is good for the environment, but we need a little help articulating why. Here are five major ways you align with Mother Earth when you capture rainwater for on-site use:


1. Reduce your Draw on Stressed Systems

(Conserve Water)

Aging water infrastructure is expensive to update; and groundwater and reservoirs are often overdrawn. When you supply a portion of your own water from the rain that falls on your roof, you reduce your draw on these stressed systems.

2. Restore the Hydrologic Cycle (a.k.a Water Cycle)

(Reduce Stormwater Impacts & Recharge Groundwater)

Environmental Benefits of Rainwater Harvesting

Click to enlarge image

In a natural landscape, approximately 50% of stormwater infiltrates into the ground, hydrating soils and recharging groundwater. About 40% evaporates, and only 10% runs off.

In developed landscapes, by contrast (e.g. our neighborhoods); only 15% infiltrates and a whopping 55% runs off! This is because water can't penetrate hardscape (roads, rooftops, parking lots, etc...).

When you collect rainwater to use in your garden, you reduce stormwater impacts by holding water on-site rather than letting it run off. As you release it later (when the ground is no longer saturated), you allow that water to sink back into the ground where it belongs, hydrating soils, nourishing plants, and recharging the groundwater beneath us. In other words, you restore the broken infiltration link in the hydrologic cycle.  If you've heard the mantra: Slow it, Spread it, Sink it, Store it! that's what we're talking about here (as opposed to Pump it, Pipe it, Pollute it!).


Stream ecosystem

3. Protect your Local Watershed

(Reduce Pollution & Erosion)

When rainwater infiltrates onsite, it is filtered naturally by the earth, and is prevented from entering storm drains and surface waters as polluted runoff. Left unmitigated, rainwater sheets off roofs and paved surfaces, collecting contaminants along the way. When stormwater runs heavy, it causes stream banks to erode as well, causing further damage to our sensitive waterways and wildlife habitat. According to the EPA, stormwater runoff is the number one source of pollution in the USA. When you Slow it, Spread it, Sink it, Store it on your site, you prevent this from happening.


4. Reduce your Carbon Footprint

(Mitigate Climate Change by Reducing Energy Use)
Footprints on beach

There is a strong nexus between energy and water in our modern world. In the state of California, for example, heating, treating, and transporting water accounts for over 20% of per-capita energy use! When you reduce your reliance on pumped and treated water sources, you contribute to a collective savings in energy at the same time.

Better yet, if you pair your rainwater catchment system with a user-friendly gravity-fed drip irrigation system, you don't need any electricity at all to run your irrigation.


5. Increase the Health of Your Garden 

Butterfly in Garden

(Mitigate Climate Change with Healthier Plants & Soils)

It's no coincidence that plants love rainwater better than any other water source. Not only is rain free of the salts, chemicals and minerals found in other water sources; by nature's design it has the perfect pH balance and nitrate delivery, ready for uptake by your thirsty garden.

Benefit from the beauty of a healthy plant and soil ecosystem, while the earth benefits from all that a healthy garden provides... including cleaner air, carbon sink, pollinator habitat, temperature and precipitation regulation, and more!

The Deeper Why: How Rainwater Harvesting Heals the Earth

We just threw a few biggies at you, so let's break down some of these environmental concepts a little more. What do we mean by temperature and precipitation regulation? Here's where we can really start to understand the interconnected nature of Earth's vital systems, and why carbon reductions alone do not address the deepest roots of climate change.

Have you heard of the urban heat island effect? Temperatures in urban areas are significantly warmer than in immediately surrounding natural areas because dark rooftops and pavement absorb extra heat that then radiates back into the environment. The more we can vegetate our towns and cities, the more we will regulate temperatures. Vegetation in urban areas also helps to improve air quality.

And precipitation regulation? Believe it or not, a lush garden will actually make rain. Get this: plants evapotranspirate, meaning they uptake water from the soils, and emit water vapor into the sky, which contributes to cloud formation. Plants also release bacteria that form "water nuclei" that attract water molecules to form rain drops. Plants ask mother nature for a drink, and she provides. Between adding more moisture to the atmosphere and sending up water nuclei to ask for rain, a landscape of lush gardens will summon more rainfall than a parched one.

Just imagine: by tapping into the otherwise-wasted water source that comes from your roof, you can create abundance in your own backyard. If others do the same, we collectively have the power to bring vitality back to an ailing environment.

So What Are You Waiting For?

No need to imagine any longer. With a full understanding of the environmental benefits of rainwater harvesting, you can align with Mother Earth and start collecting rain today. Click here to get started!

BlueBarrel Logo - Earth Day

Does Rainwater Harvesting Make Sense in Dry Climates?

Does Rainwater Harvesting Make Sense in Dry Climates?
By Jesse Froehlich, ARCSA A.P.
Founder, BlueBarrel
The answer to the question above is simple:


If you’re satisfied with that, you can stop reading here. And maybe visit www.BlueBarrelSystems.com for some great rainwater harvesting options!

If you need a little more convincing, read on.


Being in the rainwater harvesting business in arid California, I often hear comments like this:

“In our climate it rains in winter when we’re not irrigating. Then when we need the water in summer, there’s no rain. I just don’t see how rainwater harvesting makes sense with such a long dry season.”

Let’s dig into this predicament. We have to ask ourselves where our water comes from during this long, hot summer.

Whether you’re a municipal ratepayer or on a private well, there’s a good chance your water is pumped from underground aquifers. Or perhaps it comes from surface waters, or a combination. In any case, can you imagine what happens to these shared water sources as the dry summer drags on?

That’s right: they draw DOWN, DOWN, DOWN!

And unfortunately there’s another compounding factor: when it finally does rain again, this abundant fresh water resource sheets off our hardscapes, and hurries AWAY, AWAY, AWAY!

See below for an illustration of the effect of our hardscapes on nature’s hydrologic cycle. The water that is intended to infiltrate and recharge groundwater is largely prevented from doing so in our urban and semi-urban environments. The effect over time is overdraw, and in dry climates we are especially vulnerable.
Aquifer Depletion in California

That big downward-sloping blue line shows us what the California central valley aquifers have been up to (or “down” to) over a recent 40-year period: a steep decline. And with a rapidly growing population in this region, the problem is only getting worse.

So let’s consider this: What if you could do your share to counteract this trend by meeting even some of your summer irrigation demand with stored rainwater?

But this begs another question:


It is amazing just how much water you can catch off of a relatively small rooftop surface, even in a dry climate. Every square foot of catchment surface will yield about 0.6 gallons for every inch of rain. Check out the sizing tools on BlueBarrel’s website to refine the calculation for your own rooftop.

Rainwater Harvesting System

Now that you see the numbers in action, don’t forget about garages, workshops and sheds! You really don’t need much surface area to fill a rainbarrel, or even a series of them.

With these numbers in mind, the question isn’t about whether there’s enough water to catch, it’s about how much space you want to dedicate to water storage.

So let’s dig into THAT.

We all dream of a rainwater catchment system that can meet our year-round demand. (I sure do!) And as shown by the numbers above, that system may be possible even in arid California.

It is likely, however, that your budget and/or spatial constraints limit your ability to store that much water. So catch what you can and enjoy the benefits in proportion!

There are three ways to manage a rainwater catchment system if you can’t store enough water to meet your entire dry-season demand:

  1. Store what you can, use it while it lasts (which may be longer than you think if you use gravity-fed drip irrigation), and switch back to your existing water source when your rainwater runs dry.
  2. Store what you can, use it while it lasts, and then re-fill your rainwater tanks with your backup water source to continue using your gravity-fed drip system throughout the dry season.
  3. Dedicate your rainwater catchment system to a particular garden zone, like a perennial border or raised vegetable beds, and size the system to meet that zone’s irrigation need all summer long (BlueBarrel can help you strike this balance with a professional Site Assessment).

[NOTE: The BlueBarrel System includes specialty vent pieces with screened hose-swivel ports. This allows for safe and easy dry-season refilling if you’re using Strategy 2. We also offer a streamlined drip irrigation connection to ensure you are using your water efficiently.]

See below for a real-life case study from a recent BlueBarrel project at a Santa Rosa, CA residence.


Climate change projections for the North Bay predict a decrease in average annual rainfall. But there’s more to the story: this diminished rainfall is expected to come in the form of stronger storms that occur less frequently. And in fact this is exactly what we have experienced in recent years.

Ironically, this presents an additional opportunity for Rainwater Harvesters: multiple irrigation and recharge cycles over the course of a year. (This means much less storage required to meet the entire year’s irrigation need, and much higher efficacy for small rainwater catchment systems.)

Last year we experienced heavy rains in autumn followed by an exceptionally dry winter. Then we had significant rainfall again as late as June! With the first autumn rains of this year falling in late September, North Bay Rainwater Harvesters got two full irrigation cycles (one in winter and one in summer), spanning a mere 12 weeks during the hot summer season! We’re on track for the same pattern in the current cycle.

[In this article I’m not focusing on the stormwater mitigation side of things, but it’s worth interjecting that with heavier rain events (as predicted), stormwater impacts will be more severe. Rainwater harvesting takes a chunk out of your hardscape impact in addition to your draw on scarce resources–a double win. Some jurisdictions are beginning to charge stormwater impact fees based on the amount of hardscape on a site. Homeowners can usually gain off-set credits by installing rainwater harvesting systems.]


If climate change is on your mind, it’s worth noting the huge nexus between energy and water. 20% of per capita energy use in the state of California is dedicated to pumping, treating, heating, and transporting water. And in turn, there is a large water demand associated with cleaning and cooling energy generating facilities. When you reduce your draw on pumped and treated water sources, you shrink your carbon footprint as well. And with this energy savings, you contribute to a collective reduction in water needed for power delivery. Like many things in life, this is an interconnected cycle.

The conversation on climate change also brings up the awareness of a heightened need to be prepared for emergencies. Rainwater Harvesters experience tremendous peace of mind knowing they have many gallons of water stored onsite for the case of an emergency. It is important to note that stored rainwater is not potable without treatment, but it’s a wonderful emergency drinking water supply as it can easily be treated for human consumption with the same treatment methods that campers and backpackers use.

[NOTE: The BlueBarrel System includes customizable isolation valves so you can hold water in some barrels for emergency supply while using others to feed your irrigation line.]


Is it a concern that water may sit in tanks for months before being used? Not with a well designed rainwater catchment system. Depending on your system’s overflow handling, you may actually be pushing older water out as newer water enters.

But even if rainwater is held in storage for extended periods, there are a couple of best practices that help prevent problems in your tanks:

  • Use dark-colored, opaque tanks. Sun exposure will quickly lead to algal growth, but this is completely prevented when sunlight is excluded.
  • Keep your tanks in the shade. If tanks are kept out of direct sunlight the temperature will remain cool enough to prevent bacterial growth in the tanks.
  • Keep up with routine seasonal gutter clean-outs. The most important time to sweep out your gutter is in the fall before the first rains.
  • Rough-filter the water on the way into the tanks. This serves to keep out any major particulates that can cause in-tank water quality to decline.
  • If storing for emergency purposes (i.e. holding the water and not drawing it down), drain and recharge your system at least once per year.

An optimized rainwater harvesting system (in a dry climate!) will drain by the end of the dry season so you’ll get a fresh recharge at least every year. I say “at least” because this wonderful water source is also good for washing cars, defrosting windshields, rinsing boots, gardenwares and lawn furniture, and watering pets, so you may find you draw down your tanks a bit (and in turn fill them up again!) even in the thick of the rainy season.

[NOTE: The BlueBarrel System includes the code-specified pre-filtration and of course uses opaque food-grade drums. We can help you work out your system siting strategy here.]


At this point my suspicion is that here in California we’re just not dry enough! It’s the very dry southwestern states (AZ, NM, TX) with annual rainfall averages as low as 8” – 12” that are spearheading the re-birth of rainwater harvesting in the USA with favorable policies, incentives, and active licensing programs. Many California jurisdictions are beginning to follow suit.

When it’s really dry, rainwater harvesting is a no-brainer. Of course when it’s really wet, it’s a no-brainer, too. Let’s not fall victim to the Goldilocks Complex. Let’s harness this fresh abundant resource to improve our gardens, be prepared for emergencies, and restore the broken link in our urban hydrologic cycle before it’s too late!

Call your city or county to see about rebates and incentives that may be available to you for rainwater harvesting, and check out the resources at www.BlueBarrelSystems.com to customize your very own rainwater catchment system!

Runoff in Developed Landscapes

Our Broken Hydrologic Cycle

In our developed environments, groundwater doesn’t recharge the way it would in nature.

In a natural landscape, about 50% of precipitation hits the ground and infiltrates to hydrate soils and recharge groundwater. About 40% evaporates (or evapotranspirates through the metabolic activity of plants and animals); and only about 10% becomes runoff.

In a developed landscape however (including our towns and cities), with 75% impervious groundcover (think roads, parking lots, buildings, driveways, and even lawns), only 15% of water is allowed to infiltrate, while a whopping 55% becomes runoff. In an urban environment, this runoff sheets off the hardscape picking up automotive, industrial, and other pollutants along the way, rushing them to our sensitive waterways.

Rainwater Harvesting gives us the opportunity to hold this hardscape runoff onsite and allow it to infiltrate at a more natural rate if we use it to irrigate our gardens when it’s not raining.

Santa Rosa Rainwater Harvesting Analysis

Santa Rosa, CA Garden

The image above is the rainwater catchment system sizing analysis for a BlueBarrel project I completed in Santa Rosa, CA in October, 2013.

This homeowner wanted to irrigate a 250-square foot vegetable garden only with rainwater, so we sized her system to meet this irrigation need all summer long. We used a conservative safety factor to account for the especially dry conditions we’ve experienced in Santa Rosa over the last couple of years.

Our analysis showed us that even with dry years under consideration, 2,300 gallons of storage will serve this garden throughout the summer!

The lime green line shows the projected tank volume over the course of three years. We optimized the system size, so it nearly runs dry in a very dry year, but still holds some water by the time it starts refilling again in autumn. The purple line indicates supplemental water need. It’s hard to see this line in the diagram because it’s completely flat-lined at zero.

And best of all, we were able to catch all the water we need off her 480-square-foot workshop roof. Even with a small catchment surface, the system will fill with around 8” of rain. This means she gets additional bang for her buck with multiple recharges each year, depending on her water usage pattern.

We have reserved the option to tie in more rooftop surface for a quicker fill if we continue to experience extreme drought.

What can you do in your garden? Contact BlueBarrel for a professional Site Assessment.

To Boot, Rainwater is Just Too Good!

As if all this weren’t enough, serious gardeners know that rainwater is a good thing to have on hand, no matter how much rain (or how little!) you get.

Water Quality: Rainwater is the highest quality water source available to plants for three reasons:

1. Rainwater is free of the salts, minerals, and heavy metals that leach into groundwater and surface waters–a 100% soft water source.

2. If caught from a rooftop and stored in barrels, rainwater will accumulate a small amount of organic matter which can be very beneficial to your garden—a light application of fertilizer every time you water.

3. Rainwater is slightly acidic. Most organically grown plants prefer a soil pH of 5.5 – 6.5: on the acidic side of the neutral pH 7. Rainwater can help you maintain that perfect soil pH balance!

You will notice the difference, especially with young plants (they are particularly sensitive to salts and chemicals), and also with potted plants, whose containers tend to accumulate salts and minerals over time. In an open garden, you’ll also get much less soil salinization and mineral buildup with rainwater.

Gravity Feed: And for the resource-conscious gardener there’s even more! Stored rainwater is an ideal match for drip irrigation. In fact, drip irrigation will work by gravity feed, even on a flat site. Drip irrigation does not require pressure, it just requires water in the line. So as long as your water level is above the high-point on your drip line, you will get water to your garden with no added energy inputs!