Collecting rainwater in Wyoming is legal for personal outdoor use, and the state does not run a permit program for ordinary residential rain barrels. The complication sits above that simple answer: Wyoming’s constitution declares all water in the state to be public property, and large collection systems can run into the state’s water appropriation rules even when a backyard barrel never would.1Wyoming Secretary of State. Constitution of the State of Wyoming
Why Wyoming Treats Rainwater Differently
Article 8, Section 1 of the Wyoming Constitution states that the water of all natural streams, springs, lakes, and other collections of still water within state boundaries is “the property of the state.”1Wyoming Secretary of State. Constitution of the State of Wyoming That language is broader than what most state constitutions carry, and it gives the State Engineer’s Office authority over how water is allocated and used.
The state manages water under the prior appropriation doctrine, which comes down to “first in time, first in right.” Whoever first puts water to a recognized beneficial use holds a senior right, and everyone who comes later takes a junior position. When supply tightens, senior rights get filled before junior ones see any water at all.2Wyoming State Engineer’s Office. Wyoming State Engineer’s Office That system is the backdrop for every rainwater question in the state.
What the Law Says About Rain Barrels
Wyoming has no statute that specifically addresses residential rainwater collection. Nothing explicitly permits it, nothing explicitly bans it, and the State Engineer’s Office has not created a permit category for rain barrels or small cisterns. The constitutional language is broad enough that it could theoretically reach rain falling on your roof, but the state has not written rules to apply it that way.
The City of Laramie’s official FAQ states the practical position plainly: “At this time the state does not have a permit process and there is no City of Laramie ordinance preventing the use of rain barrels. Citizens are able to catch storm water for personal use without regulation.”3City of Laramie. Frequently Asked Questions That reflects the reality across most of Wyoming. Homeowners routinely set up rain barrels for gardens and landscaping without filing paperwork or paying fees.
None of that makes rainwater a free-for-all. The constitutional framework still applies, and the State Engineer’s Office keeps broad authority over water appropriation. Small-scale collection for personal outdoor use operates below the regulatory radar; anything large enough to affect downstream users can draw scrutiny under existing water rights law.
When Collection Gets Big Enough to Need a Permit
Wyoming law requires anyone appropriating state water to obtain a permit from the State Engineer’s Office.4University of Wyoming. Wyoming Water Law: A Summary A homeowner catching a few hundred gallons off a roof for tomato plants will not trigger that requirement. A rancher installing a 10,000-gallon cistern system fed by barn rooftops is a different situation, because that volume can realistically reduce runoff feeding a stream where someone else holds a senior right.
During periods of limited supply, water goes to the earliest rights first, and later appropriators get cut off entirely.4University of Wyoming. Wyoming Water Law: A Summary If your collection system is large enough to cut the flow reaching a senior holder’s diversion point, you are on shaky legal ground without a permit. That is where the real enforcement risk lives, not with backyard barrels.
Farms, Ranches, and Commercial Property
Farms, ranches, and commercial operations face more scrutiny when capturing precipitation. Large roof areas on barns, warehouses, and other structures can collect substantial volumes, and that water would otherwise flow into the local watershed. The State Engineer’s Office evaluates whether a new appropriation would injure existing downstream right holders before approving any permit.
Agricultural applicants typically need more documentation, including mapping that shows how the proposed collection area relates to the local watershed. The maps should identify the catchment surface, storage location, and the land where collected water will be applied. If you run a commercial property and want to install a large-scale system, contact the State Engineer’s Office before you build. The office manages appropriation, distribution, and application of water to beneficial use statewide, and its staff can tell you whether your specific project needs a formal permit.2Wyoming State Engineer’s Office. Wyoming State Engineer’s Office
How to Apply If You Need a Permit
If your project crosses into permit territory, you file through the State Engineer’s Office using one of its surface water forms. Form SW-1 covers new diversions from streams, including ditches, pipelines, and water hauls, at a $50 filing fee. Reservoir-type storage under 20 acre-feet uses Form SW-3A at $25. Stock-only reservoirs under 20 acre-feet use Form SW-4, also $25.5Wyoming State Engineer’s Office. Surface Water Applications and Forms Most standard applications run $50, with smaller special-application permits at $25.6Legal Information Institute. Wyoming Code of Regulations 037-1 Section 1-3 – Surface Water Fees
The application asks for a legal description of the property by township, range, and section; the location and type of catchment surface; the storage capacity of your tanks or cisterns; and how you intend to use the water. The State Engineer’s Office reviews each application to determine whether granting the permit would injure existing water right holders. The process takes several months.
Penalties for Unauthorized Diversion
Enforcement against backyard rain barrels is essentially nonexistent, but Wyoming has real penalties for larger unauthorized diversions. Violating the state’s water appropriation laws is a misdemeanor. After written notice from the State Engineer’s Office or Board of Control, each day of continued noncompliance counts as a separate offense, with fines up to $1,250 per day. Failure to comply with a written order can also carry up to three months in jail on top of the daily fines.7Wyoming Legislature. Wyoming Statutes Title 41 – Water
Those penalties target people who divert significant water from streams or build unpermitted wells and reservoirs, not homeowners with a 55-gallon barrel under a downspout. The statutory authority is there, which is why large-scale operators should not skip permitting.
Drinking Water Is a Separate Question
Using collected rainwater for drinking brings in health and safety requirements administered by the Wyoming Department of Environmental Quality rather than the State Engineer’s Office. Potable rainwater systems need filtration and disinfection to meet safe drinking water standards, so contact the department for specific guidance before relying on harvested rain as a household water source. If your property runs both municipal water and a rainwater system, label the tanks and outdoor taps as non-potable and keep the two sets of plumbing clearly separated.