Is Rainwater Harvesting Illegal? Colorado’s Journey to “Legalize It”

By Jesse Savou, M.A., ARCSA A.P., Founder of BlueBarrel Rainwater Catchment Systems

Legalize It T-ShirtThe phrase “Legalize It” has taken on special significance in the great state of Colorado as of late. And the lesser known reason is the epic legalization of rainwater harvesting—albeit on a limited basis—that went into full effect on August 10th, 2016. 

While Colorado's allowance of 2 rain barrels per household is huge news to celebrate, I want to start by highlighting the fact that rainwater harvesting is actually perfectly legal in most places. Colorado was one of the only states in the USA that imposed broad-brush bans on collecting the water that falls on one's own roof.

One of the most common myths about rainwater harvesting is that it is illegal. Every time we demo our rain barrel systems at an event, we get a good handful of people saying “too bad that’s illegal!” Funny thing though, when asked, (unless they’re from Colorado or Nevada) none of these folks can ever cite a law, or any source more official than a neighbor or friend.

I don’t know where these myths generate, but if anyone ever had a neighbor that tried to permit a rainwater catchment system and got rejected, I’m sure it spreads like wildfire that the government won’t even let you capture the water that falls on your own roof.

Rain Barrel System

Says the owner of this 2-barrel BlueBarrel System: "The installation went well and I just received a rebate that covers the total cost of the system!"

In fact, it's possible this myth traces back to a single case in Oregon, where a man went to jail for erecting large dams on his property to obstruct the flow of water across his site. That's a little different. Or perhaps it's the case of Colorado that has caused this rumor to spread like rhizomes, beyond its reasonable boundaries.

Truth be told, in most places rainwater harvesting is perfectly legal and always has been, although perhaps wrought with a reputation of lawlessness because there simply wasn’t much knowledge about it.

And in recent history, many jurisdictions have even begun to incentivize rainwater harvesting as a sustainability measure. The environmental benefits of rainwater harvesting are so great, both in terms of water conservation and stormwater management, that cities, counties, and water agencies across the nation are offering rebates for rain barrels, rain gardens, and other techniques for slowing the flow of water across the landscape and infiltrating it on site. (The popular mantra for this movement is “slow it, spread it, sink it, store it!” … this, as opposed to “pump it, pipe it, pollute it”).


Rainwater Code: California as a Case Study

Many states have adopted code in recent years to establish simple guidelines for rainwater catchment systems. While the mere idea of code and regulations makes many people cringe, at BlueBarrel we support the code because it is comprised of simple common-sense guidelines for storing water safely, and has helped make regulators more comfortable with rainwater harvesting. In the state of California and elsewhere, the code is formatted to outline requirements for a non-permitted system, meaning if one follows the guidelines, no permit is necessary, and we can feel safe knowing that things like mosquito abatement, tank safety, and safe storage of water have been handled properly. (Our BlueBarrel Rainwater Catchment System™ is code compliant, by the way!)

In the past, a building official may have rejected a permit application simply because there were no established guidelines to evaluate it against. Maybe this is where some of those pesky rumors came from! And those who avoided the building official (which in this case was probably a smart thing to do), may have smirked that they were somehow getting around the law. But now that the rules are clear, so is the path for the average homeowner (or renter!) to become more sustainable by installing a rainwater catchment system. And as of August 10th, 2016, the path is clear for Coloradans as well.


Rainwater Harvesting in Colorado

The Colorado special: BlueBarrel's 2-Barrel system - exactly 110 gallons of fully accessible water storage.

The Colorado special: BlueBarrel's 2-Barrel system - exactly 110 gallons of fully usable water storage. (Note the tap is under the barrels, so the user can drain every last drop.)

So what's the story with Colorado? While rainwater harvesting was permitted in specific situations already, Colorado was one of the only places in the USA (in the world, maybe?) that the average homeowner was not allowed to place a bucket under a downspout. But hard-fought legislation legalizes rainwater harvesting on a limited basis, and thanks to the recent passage of House Bill 16-1005, most Colorado residents are now allowed two rain barrels (up to 110 gallons of storage) per household.

Why the such a strict limitation? Colorado has a very unique and complicated (and some would say antiquated) set of laws governing water rights. With the Colorado River serving 18 states and parts of Mexico, the prior appropriation doctrine states that water rights are held by those who first staked claim (“appropriated”) the water from the Colorado River, not necessarily those who live in the watershed. There is a fear that if upstream users harvest water from their roofs, it will diminish the yields for those scattered entities (senior water rights holders) who own the rights to draw from the Colorado River.


Do Senior Water Rights Holders have anything to worry about?

(Read: A Simple Lesson on How the Hydrologic Cycle Works)

Two barrels tucked in a shady area - ready for rain!

Two barrels tucked away in a shady spot in the garden - all ready for the rain!

While it may seem logical to assume the more water we harvest in tanks and barrels, the less water makes it back to the river; whole-systems thinking reveals that rainwater harvesting actually increases hydrologic health, and in most cases will actually help maintain base levels in rivers, lakes, and streams.

Why is this? In a natural environment, roughly 50% of the rain that falls on the ground infiltrates to hydrate soils, recharge shallow and deep aquifers, and maintain base levels in rivers and streams. About 40% evaporates, and the remaining 10% becomes runoff.

Did you catch that? When water infiltrates, it actually replenishes the water table and this is the primary force that keeps our rivers flowing. In a natural environment, only a minimal amount of water runs off the surface to replenish waterways.

Diagram by Jesse Savou, showing infiltration and runoff figures in natural versus developed environments.

Let’s compare that to developed environments, like our cities, towns, and fields. In a developed landscape with 75% impervious surface (think roads, parking lots, lawns (yes, lawns!), and (uhem) your roof)... only about 15% of rainfall infiltrates, and a whopping 55% becomes runoff.

Yikes! We’ve virtually flipped nature on its head as far as the hydrologic cycle is concerned, most notably by preventing water from infiltrating to replenish the water table. This is precisely the reason that droughts are so pronounced in arid western states like Colorado and California.

But what about that 55% runoff that our hardscapes create? Surely that helps the streams somewhat, right? While this runoff does make its way to streams eventually, the extreme quantities of runoff generated in our urban and suburban environments have become one of the most pressing environmental issues of our time.

Also known as “nonpoint source pollution,” these amplified volumes of runoff sheet over our hardscapes, picking up automotive, industrial, and agricultural chemicals along the way, and swiftly deliver those to our sensitive waterways. As if that weren’t enough, the increased runoff delivery also causes streambanks to erode, stripping our waterways of their natural defenses and making the ecosystem even more vulnerable. According to EPA, stormwater runoff is the single largest contributor to water pollution.


The role of Rainwater Harvesting in restoring the hydrologic cycle

Hydrologic Cycle

The hydrologic cycle: naturally recycling water since the beginning of time.

In case you’ve lost the thread here, let’s take one last step to really tie rainwater harvesting back into the equation of hydrologic health - just to prove that Colorado is on the right track by allowing residents to harvest rainwater.

Now that we see how much impact we’ve had on the hydrologic cycle by creating so much hardscape in our environment, catching a little (or a lot!) from our roofs is a common-sense measure to mitigate some of the negative impacts of that hardscape.

While the initial harvest helps take the peak off of stormwater loads, suddenly we have water stored for use between rains - an especially valuable resource in drought prone areas.

If you’ve never done the simple calculation to figure out how much runoff your roof (however small) generates, it may just blow your mind. To give you an example, a single inch of rain falling on 1,000 square foot rooftop will generate more than 600 gallons of high quality irrigation water. That’s enough to fill 11 (count ‘em - e l e v e n !) of our 55-gallon rain barrels. And remember, that’s just what’s available from a single inch of rain falling on quite a small roof!

You can use our rainwater calculator to see how much rainwater is available from your roof in an average storm, or an average year .

Those who really get into rainwater harvesting will find themselves bleeding full rain tanks out between storms, simply so they can catch more the next time it rains. In the dry times between rains, thirsty plants, soils, and aquifers really appreciate the influx of high quality water, so it’s no waste at all to let it infiltrate. This, in effect, begins to mimic the more natural rates of infiltration that we would see if our roofs weren’t there in the first place.

Rain barrels Colorado

This Colorado customer painted his BlueBarrel System to match the house.

The average Coloradan rainwater harvester, with 110 gallons of water storage, may actually catch many times that in an average year. But considering the alarming volumes of runoff our rooftops create (which in turn pollute the river), Colorado’s allowance for two rain barrels should hardly scare the owners of the water rights.

In fact, once Colorado gets a chance to observe the positive impact of rainwater harvesting, one can only hope that Colorado, like most places, will open up and allow unlimited storage. Rainwater Harvesting is legal, and after all, it helps us remember that this precious and limited resource—when managed sustainably—actually is abundant, and there is plenty to go around.



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