Rainwater Harvesting Laws You Need to Know About (2023)

This article has been updated for 2023.

Rainwater harvesting as a primary water supply is a relatively new idea and industry. Therefore, the laws around rainwater harvesting can be a concern. As of right now, the federal government does not regulate rainwater harvesting at all, but rather, leaves it up to the individual state governments.

Make sure that your rainwater harvesting trade contractor is aware of and complies with local codes and regulations.

[This post is not legal advice. Make sure to do your own due-diligence to ensure that you are compliant with federal, state, and local codes & regulations]

Is it Illegal to Harvest Rainwater?

In almost every case, no.

Out of the lower 48 states in the U.S., Colorado, Utah, Nevada, Illinois, and Arkansas are the only states that are currently heavily regulated to keep homeowners from harvesting and using the rain that falls on their property.

But in most states, rainwater harvesting is either not regulated at all, or actually encouraged by the state government as a method for water conservation, stormwater management, and water availability.

Rainwater is a resource. And once it falls on your property, it’s yours. Free to use.

Will Rainwater Harvesting Become Illegal?

If it follows the current trajectory, this is a resounding no. More and more states are adopting rainwater harvesting and even using it on public and government buildings. Laws are in place to provide incentives for rainwater harvesting in multiple states, and this seems to be a growing trend.

Organizations like the American Rainwater Catchment Systems Association (ARCSA), are continually working with government organizations to help rain harvesters all over the country.

Even the states that do have laws and regulations on rainwater harvesting are in the process of getting these removed.

There is a need for stormwater retention for states east of Texas, and there is a need for water availability for those west of Texas. Rainwater harvesting is a solution to both of these issues.

Requirements through the NPDES to keep rivers, lakes, and streams clean through stormwater retention is more important to the federal government than possible water rights based on stormwater runoff.

Why Are There Regulations on Rainwater Harvesting?

Old statutes and codes that were derived from an old sense of thinking, primarily.

In the case of Colorado, they have a 120-year-old law that implies that rainwater harvesting is illegal since that rainwater could flow downstream into someone else’s water supply, which would be taking from them if one collected the rain.

There is also some blanket regulations in case of improper treatment. But compared to well water, rainwater is rather simple to treat to ensure a high-purity source.

Speaking of well water, in the states that do have regulations on rainwater harvesting, there are some that include exceptions for homes that rely on well water as their water supply.

Rainwater Harvesting Regulations for Each State:

Listed below are each state’s various regulations and other information about rainwater harvesting. For resources directly from the U.S. government, you can also view this interactive map by the Office of Energy Efficiency & Renewable Energy.

Alabama

‍No regulations or laws against rainwater harvesting.‍

Alaska

No regulations or laws against rainwater harvesting.

Arizona

No regulations or laws against rainwater harvesting.

Arkansas

Rainwater Harvesting systems must meet plumbing codes and be designed by an engineer, additionally, they must only be for non-potable use.

California

No regulations or laws against rainwater harvesting.

Colorado

The only state that it is completely illegal to harvest rainwater. Other than that each house is allowed up to 110 gallons of rain barrel storage.

Connecticut

No regulations or laws against rainwater harvesting.

Delaware

No regulations or laws against rainwater harvesting.

Florida

No regulations or laws against rainwater harvesting.

Georgia

No regulations or laws against rainwater harvesting.

Hawaii

No regulations or laws against rainwater harvesting.

Idaho

Legal to capture rainwater off roof structures and the ground as long as the rain has not entered a natural waterway.

Illinois

Rainwater harvesting can only be used for potable use.

Indiana

No regulations or laws against rainwater harvesting.

Iowa

No regulations or laws against rainwater harvesting.

Kansas

No regulations or laws against rainwater harvesting.‍

Kentucky

No regulations or laws against rainwater harvesting.

Louisiana

No regulations or laws against rainwater harvesting.

Maine

No regulations or laws against rainwater harvesting.

Maryland

No regulations or laws against rainwater harvesting.

Massachusetts

No regulations or laws against rainwater harvesting.

Michigan

No regulations or laws against rainwater harvesting.

Minnesota

No regulations or laws against rainwater harvesting.‍

Mississippi

No regulations or laws against rainwater harvesting.‍

Missouri

No regulations or laws against rainwater harvesting.

Montana

No regulations or laws against rainwater harvesting.

Nebraska

No regulations or laws against rainwater harvesting.‍

Nevada

Rainwater harvesting is only allowed for non-potable use.

New Hampshire

No regulations or laws against rainwater harvesting.

New Jersey

No regulations or laws against rainwater harvesting.

New Mexico

Some rainwater harvesting systems need a permit, but this state offers payable incentives for green building such as rainwater harvesting.‍

New York

No regulations or laws against rainwater harvesting.‍

North Carolina

Rainwater harvesting is encouraged due to water conservation efforts.

North Dakota

No regulations or laws against rainwater harvesting.

Ohio

Rainwater harvesting is legal, but there are codes and regulations that must be followed.

Oklahoma

No regulations or laws against rainwater harvesting.

Oregon

Rainwater harvesting is legal, but only using rooftop surfaces.

Pennsylvania

No regulations or laws against rainwater harvesting.‍

Rhode Island

No regulations or laws against rainwater harvesting.‍

South Carolina

No regulations or laws against rainwater harvesting.‍

South Dakota

No regulations or laws against rainwater harvesting.

Tennessee

No regulations or laws against rainwater harvesting. (More on Tennessee below)

Texas

Highly encouraged. Some counties even offer a tax incentive. And there is an exemption on sales tax for rainwater harvesting systems.

Utah

2,500 gallons max for rainwater harvesting systems. A permit is required

Vermont‍

No regulations or laws against rainwater harvesting.

Virginia

No regulations or laws against rainwater harvesting.

Washington

No regulations or laws against rainwater harvesting.

West Virginia

No regulations or laws against rainwater harvesting.

Wisconsin

No regulations or laws against rainwater harvesting.

Wyoming

No regulations or laws against rainwater harvesting.

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As you can see, most states either have no regulations or are in favor of rainwater harvesting. This aligns with the trend we are seeing today.

Rainwater Harvesting in Tennessee

There are many homes and custom homes in Tennessee that are currently using rainwater harvesting as the primary water for their family, drinking, washing, bathing, and for whatever else they might use water. There are no regulations in Tennessee on how much you can capture and use. Tennesseeans are using this natural resource and benefiting from water quality, water availability, stormwater retention, and eco-friendliness

Based on stormwater retention laws, one could assume that rainwater harvesting is rather encouraged! In fact, the University of Tennessee is currently using rainwater harvesting on new dormitories for that specific purpose, but also are using the water for toilet flushes and laundry.