Why Colorado Banned Rain Barrels, and What Changed in 2016
The only real rainwater ban in the country came from western water law, not from bureaucracy. Here is the reasoning, the 2016 repeal, and why the story outlived the law.
For most of a century, Colorado was the one state where putting a barrel under your downspout was genuinely against the law. Not a permit you skipped. Actually prohibited. What the statute says now is short enough to read in a minute.
That ended in 2016. The explanation is more interesting than “bureaucracy,” and it is still misunderstood by nearly every page that repeats the story.
The logic behind it
Colorado, like most western states, allocates water by prior appropriation, which is why the legal picture differs so much by state. Rights are ranked by seniority, oldest first, and in a dry year the junior holders get nothing so the senior ones get their full allocation. It is a harsh system and it exists because the water genuinely runs out.
Under that doctrine, rain that falls on your roof is not treated as yours. It is treated as part of the stream system it would eventually have reached, already spoken for by someone downstream with a decree that may predate your house by eighty years. Capturing it in a barrel was, legally, diverting water that belonged to a senior rights holder.
That is not an absurd position once you accept the premise. It is the same reasoning that stops you damming a creek across your own land.
The premise is where it gets shaky. A 2007 study commissioned by the state found that the overwhelming majority of precipitation falling on a residential roof never reaches a stream at all. It evaporates or is absorbed. The volume a household barrel would intercept is close to a rounding error against the system it was theoretically protecting.
What the 2016 law did
HB16-1005 made residential rain barrels legal, with limits that still hold today.
Two barrels per household, 110 gallons combined. Single-family homes, and multi-family buildings of four units or fewer. Sealable lids required. The water may irrigate outdoor lawns, plants and gardens, on the property it was collected from. No indoor use and no drinking.
Rural households with exempt well permits have a separate route through the Division of Water Resources, which allows larger rooftop collection tied to the uses already in their well permit.
The part that survived the repeal
Collecting rain in Colorado does not give you a water right, and that distinction is the one everybody misses.
The State Engineer retains authority to curtail individual rain barrels if a downstream rights holder can demonstrate they are being harmed. Nobody expects that to happen to a homeowner with two barrels, and it has not. But the legal architecture is unchanged. What the 2016 law granted was permission, not ownership.
That is why the caps exist and why they are the size they are. The legislature was carving out an exception small enough that it could not credibly injure anyone senior.
Why the story outlived the law
Search for whether rainwater collection is illegal and you will still find pages listing Colorado as a banned state, describing rules that stopped applying a decade ago.
Part of that is ordinary link rot in an industry that rewrites other people’s articles. Part of it is that the original story was genuinely striking. “There is a state where you cannot legally catch rain” is memorable in a way that “the state amended its position in 2016” is not.
It has also been useful to people selling things. A ban on catching rain fits neatly into a story about being prevented from providing for yourself, and that story sells water products. The correction is duller and does not.
What to take from it
If you are in Colorado: two barrels, 110 gallons, outdoors, same property. Fine for a garden, not a water supply.
If you are anywhere else: this was never your rule, and it is not the reason to check your own state. The real reasons are the permit thresholds on larger cisterns and whatever your HOA has to say.
And the broader lesson is worth keeping. On this topic in particular, the confident answer you find repeated everywhere may be describing a law that no longer exists. Check the statute, and check when someone last read it.