Is It Illegal to Collect Rainwater?

You can legally collect rainwater in all fifty states. There is no state where putting a barrel under your downspout is a crime.

What varies is whether conditions come attached. A handful of states cap how much you may store, several require a permit above a threshold, a few restrict what the water may be used for, and a surprising number pay you to do it.

The belief that it is banned outright traces almost entirely to one state, and that law changed a decade ago.

Why people think it is illegal

Colorado spent over a century as the strictest state in the country on this, because of how western water law works.

Under prior appropriation, the doctrine most western states use, water rights are allocated by seniority and rain that falls on your roof is legally considered part of the stream system it would have eventually reached. Capturing it was, in principle, taking water that belonged to a downstream rights holder.

That principle produced a genuine restriction, it got reported widely, and the story outlived the law. Colorado passed HB16-1005 in 2016, and residential rain barrels have been legal there ever since. Sites still publish “the states where rainwater collection is illegal” with Colorado at the top, describing rules that stopped applying a decade ago.

What Colorado actually allows now

Worth stating precisely, because it is the state people ask about and because it shows what a real restriction looks like.

Two barrels per household, holding no more than 110 gallons combined. Single-family homes and multi-family buildings of four units or fewer. Each container needs a sealable lid. The water may be used to irrigate outdoor lawns, plants and gardens on the same property it was collected from. Not indoors, and not for drinking.

Rural residents with exempt well permits can apply separately to the Division of Water Resources for a rooftop precipitation collection system permit, which allows larger volumes.

One detail most summaries miss: collecting rain in Colorado does not give you a water right. The State Engineer retains authority to curtail individual barrels if a rights holder can show they are being harmed. That has not happened to a homeowner with two barrels, and it is the legal reality underneath the permission.

The categories that actually matter

Rather than a fifty-row table you will not read, the rules sort into four kinds.

Unrestricted. Most states. Collect what you want, use it how you like, no permit and no cap. Most of the eastern half of the country sits here.

Regulated by volume or use. A cap on gallons, a limit to outdoor or non-potable use, or both. Colorado is the strictest example. Others attach conditions rather than caps.

Permitted above a threshold. Nothing at all for a rain barrel, something for a cistern past a certain size. This is the most common form of regulation and it almost never affects a household.

Encouraged. States and municipalities offering rebates on barrels and cisterns, sales tax exemptions on equipment, or tax credits on systems. Texas and Arizona have well-established programs, and many individual water districts run their own regardless of what the state does.

A household with one or two barrels is unaffected in the overwhelming majority of the country. If you are planning a cistern that will supply a house, that is when the threshold rules become real and worth reading properly.

The rules that are more likely to affect you

Two things catch people out far more often than state law.

Your HOA. Covenants restricting the appearance of a yard have blocked more rain barrels than any statute. Several states have passed laws limiting an association’s ability to ban them outright, which tells you how common the conflict is. Check your covenants before you check your state code.

Local plumbing and health rules. If you intend to plumb collected water into a house, that is a building code question and a health department question, separate from whether collection is legal. Indoor use, and potable use in particular, is where local rules bite.

How to check your own state properly

Do not trust a table on a content site, including a summary of one. Nearly every ranking page on this topic is a rewrite of another page, and Colorado is proof of how long an error survives that way.

Go to your state’s Division of Water Resources, Department of Environmental Quality or equivalent, and search for rainwater or precipitation harvesting. Your state’s university extension service usually publishes a plain-language version with the statute cited, which is the fastest reliable route. If a page does not cite a statute and does not say when it was last checked, treat it as a starting point rather than an answer.

We keep a page per state with the citation and the month the statute text was last read, starting with Colorado, Nevada, California, Oregon and Texas. States get added as they are verified rather than all at once, because a confident answer about the wrong law is worse than no answer.

The practical answer

For almost everyone reading this: legal, no permit, no cap, put the barrel out.

If you are in Colorado, two barrels and 110 gallons, outdoor use only. If you are planning something larger than a couple of barrels, check the permit threshold in your state. If you belong to an HOA, read the covenants first, because that is the rule most likely to stop you.

And whatever your state says about collecting it, none of them are telling you it is safe to drink. That is a separate question with a separate answer.