Yes, rainwater harvesting is legal in Illinois. While the state has no comprehensive regulations, it encourages rainwater reuse for non-potable purposes. Local codes may vary, so residents should check with municipal authorities before installing systems.
The key piece of legislation is the Rainwater Capture Act of 2012, a forward-thinking law that makes it crystal clear.
residents, businesses, and municipalities are allowed to capture, store, and reuse rainwater for non-potable purposes.
That means watering your garden, irrigating your lawn, or even managing stormwater runoff from commercial rooftops is fair game, as long as the water isn’t used for drinking.
Photo Source -> Rainwater Cistern In Lake County, Illinois
The Rainwater Capture Act of 2012: A Step in the Right Direction
Passed over a decade ago, the Act was Illinois’ answer to increasing concerns over water conservation and stormwater management.
The law gives both private property owners and local governments the green light to implement rainwater harvesting systems without needing to tiptoe around unclear legal boundaries.
The bill was sponsored by lawmakers who recognized the environmental and financial benefits of reducing dependence on municipal water for non-potable uses. It even encouraged the Illinois Department of Public Health to adopt rules to guide the safe use of captured rainwater, particularly for larger systems used in public buildings and businesses.
And while it’s true that the law doesn’t go so far as to regulate or endorse potable uses (like drinking or cooking), it opens the door for homeowners and organizations to build sustainable, cost-effective systems with confidence.
Illinois: A Supporter of Sustainable Water Practices
As someone who’s spent the past 20 years helping folks build rain capture systems from the ground up, I can tell you, Illinois is ahead of the curve.
The state views rainwater harvesting not as a fringe eco-hack, but as part of the solution to stormwater pollution, rising water bills, and infrastructure strain.
In recent years, cities across Illinois have installed rain gardens, green roofs, and bioswales as part of their commitment to “green infrastructure.” And homeowners, gardeners, and even preppers are getting in on the action with systems as simple as a barrel under a downspout or as complex as multi-barrel cisterns with integrated irrigation. The enthusiasm is growing, but so are the misconceptions.
What Is the Rainwater Capture Act of 2012?
The Rainwater Capture Act of 2012 was a landmark step for Illinois.
While many states were still trying to decide whether individuals even had the right to collect rain, Illinois passed legislation that not only legalized rainwater harvesting, but also encouraged its responsible use across residential, commercial, and municipal settings.
A Law Rooted in Conservation and Common Sense
The law was introduced in response to growing concerns about stormwater runoff, rising infrastructure costs, and urban flooding, particularly in the Chicagoland area.
Runoff from roofs and pavement was overwhelming city systems, carrying pollutants straight into rivers and lakes. Lawmakers realized that slowing and capturing rain at the source, on rooftops, could reduce the burden on storm drains while giving homeowners a practical way to conserve water.
That’s where rain barrels, cisterns, and rain gardens came in.
The Rainwater Capture Act essentially gave Illinoisans the green light to build these systems without legal risk, as long as the water is used for non-potable purposes.
What the Law Does Allow
Under the Act, individuals and businesses can legally collect and use rainwater for:
Landscape irrigation
Cooling systems
Toilet flushing (in commercial systems)
Stormwater detention
This applies whether you’re collecting water in a basic rain barrel or designing a large-scale underground cistern for your business. The law applies to residential, commercial, and municipal properties alike. So whether you’re a homeowner looking to water your vegetable garden or a school district installing a green roof, the state has your back.
Furthermore, there’s no state-imposed limit on how much rainwater you can collect in Illinois, at least for non-potable use.
It’s also worth noting that Illinois encourages these systems to be installed as part of green infrastructure initiatives, which are popping up in city and village codes statewide. If anything, the state would like to see more people jump on board.
What the Law Doesn’t Cover
That said, the law draws a clear line at potable use, drinking, cooking, or bathing in harvested rainwater isn’t regulated under this act.
That doesn’t mean it’s illegal; it just means Illinois hasn’t written the rules yet for treating rainwater to drinking water standards. If you're considering a potable system, you'll want to work with certified filtration and treatment professionals and definitely talk to your local public health department.
How Illinois Compares to Other States
It surprises a lot of people to learn that in the United States, land of innovation and independence, some states have historically restricted rainwater harvesting. That’s right: in certain regions, collecting water from your own rooftop was, for years, tightly controlled or outright banned.
Luckily, Illinois is not one of those states. In fact, they’ve taken the opposite approach.
Rain Harvesting: Legal Gray Area in Other States
Let’s break it down.
While today the trend is moving toward broader acceptance, some states have struggled with conflicting water rights laws, particularly in the West.
In states like Colorado and Nevada, water rights are tied to historical claims, meaning rain that hits your roof may technically “belong” to someone downstream who holds a legal claim to it. It sounds crazy, but that’s the legacy of managing scarce resources in arid regions.
Even when laws aren’t restrictive, confusion often reigns. Some states still require permits for even the simplest systems. Others limit how much water you can collect, or where and how you can use it.
Why Would Anyone Outlaw Rain Collection?
It’s a fair question, and one I’ve heard from customers more times than I can count. The rationale comes down to a combination of outdated legal frameworks and concerns about environmental disruption. In water-scarce regions, governments have argued that interfering with natural runoff can disrupt aquifer recharge or deprive downstream users.
But let’s be honest: those arguments don’t hold much water (pun intended) when it comes to individual rooftop collection for non-potable use. If anything, harvesting rain in urban and suburban areas keeps water local and reduces the burden on overworked municipal systems.
Start Smart With AquaBarrel
At AquaBarrel, we’ve spent two decades helping folks turn curiosity into confidence. We don’t just sell barrels, we teach, we troubleshoot, and we stand by our products long after the sale is made.
We’ve helped thousands of people across Illinois and beyond build rainwater systems that are safe, compliant, and built to last. Whether you need adapters for a weird downspout, advice on overflow drainage, or just a real person to walk you through your options, we’re here.
Our site is packed with helpful resources, video tutorials, and tools to get you started the right way. And if you're looking for something custom or commercial-scale, we've got the experience and the parts to make it happen.