No, it is not illegal to collect rainwater in Maine. The state has no statute restricting or prohibiting rain capture, and no state permit, license, or fee applies to basic systems like barrels or cisterns. Rules only come into play once you connect a collection system to your home’s plumbing, build something large enough to trigger local zoning, or want to drink what you collect.
Why Maine Doesn’t Restrict Rainwater Collection
Maine has never passed a law limiting a property owner’s ability to catch rain. That is different from several Western states, where prior appropriation rules can mean rainwater landing on your roof technically belongs to a downstream rights holder. Maine treats diffuse surface water under the reasonable use doctrine, which gives you broad freedom to capture precipitation on your own land.
The state’s surface water statute does address situations where someone unreasonably alters the flow of surface water in a way that damages a neighbor’s property, but it does not restrict collecting rain before it hits the ground or runs off your roof.1Maine Legislature. Maine Code Title 17 2808 – Alteration of Surface Water Flow Because there is no prohibition, there is also no statute affirmatively saying collection is allowed. You do not need to register your system, pay a collection fee, or report how much water you gather.
When Plumbing Code Rules Kick In
A rain barrel sitting under a downspout involves no regulated plumbing. The rules start to apply when you install a larger system with tanks, pumps, or pipes that connect to your home. Maine’s plumbing code includes a dedicated chapter for nonpotable rainwater catchment systems and a separate appendix covering potable catchment.
If you tie a collection system into household plumbing, three requirements matter most:
- Your system must include an air gap or an approved backflow prevention device at every point where collected rainwater could contact the drinking water supply.
- You cannot connect a pipe carrying non-drinking water directly to a drinking water line. The two systems must be physically separated to prevent contamination of your well or municipal supply.
- All non-drinking-water piping must be durably labeled so anyone working on the plumbing can tell it apart from potable lines.
These requirements track Maine’s broader regulatory framework for protecting water quality.2Legal Information Institute. Maine Code of Maine Regulations 10-144 Chapter 200 5-2 – Plumbing System
Whether Your Town Enforces the Building Code
The Maine Uniform Building and Energy Code is mandatory only in municipalities with more than 4,000 residents. Smaller towns are not required to enforce it, and they cannot adopt a different building code on their own.3Maine Legislature. Maine Code Title 10 9724 – Application
If you live in a smaller rural town, the state building code may not be actively enforced where you are, though the plumbing code still applies to any connection to a public water supply. Building to code standards anyway is the smart play. It protects your well water and matters if you ever sell the property.
Local Zoning for Larger Tanks and Cisterns
Maine gives its municipalities broad home rule authority. Under Title 30-A, Section 3001, a town can adopt ordinances on any subject the legislature can delegate, unless state law expressly prohibits it.4Maine State Legislature. Maine Code Title 30-A 3001 – Ordinance Power That means your town can set rules on where you place a large cistern or collection tank, how far it must sit from property lines or roads, and whether it needs screening or a specific color in a historic district.
A simple rain barrel usually falls below the threshold that triggers permit requirements. A larger system with above-ground tanks or an underground cistern may need site plan review, especially if the code enforcement office treats the tank as an accessory structure. Some towns require permits for any structure above a set size, regardless of its purpose. Call your local code enforcement officer before investing in anything beyond a basic barrel setup.
Penalties if You Skip a Required Permit
Penalties under Maine land use law are civil, not criminal, but they stack up fast because they are assessed per day. Starting construction or installing a system without a required permit carries a penalty between $100 and $2,500 per day. A specific code violation carries a penalty between $100 and $5,000 per day. In an area zoned for resource protection, the maximum climbs to $10,000 per day. Repeat violators penalized for the same type of violation within the previous two years face fines up to $25,000 per day.5Maine State Legislature. Maine Code Title 30-A 4452 – Enforcement of Land Use Laws
Ignoring a correction notice for a couple of weeks can mean thousands in accumulated penalties. If the economic benefit of the violation exceeds the standard penalty range, the municipality can increase the fine to twice that benefit.5Maine State Legislature. Maine Code Title 30-A 4452 – Enforcement of Land Use Laws
Drinking Collected Rainwater
Most Maine residents collect rainwater for gardens, car washing, or livestock. Those uses involve no health department oversight. Things change if you want to drink the water or pipe it to indoor faucets and showers.
Maine’s Rules Relating to Drinking Water, at 10-144 CMR Chapter 231, set safety requirements for public water systems, covering operation, water quality, and enforcement.6Maine Center for Disease Control and Prevention. Maine Code of Maine Regulations 10-144 Chapter 231 – Rules Relating to Drinking Water They are aimed at public systems rather than a single household’s private setup. If your collection system serves multiple dwelling units or qualifies as a public water supply, those drinking water standards apply in full.
For private household use, treatment still matters from a health standpoint. Rooftop runoff can carry bird droppings, pollen, dust, and chemical residues from roofing materials. A potable system should at minimum include sediment filtration, activated carbon treatment, and UV disinfection or chlorination. The potable catchment appendix in Maine’s plumbing code gives the specifications to follow.
Avoiding Nuisance Claims and Mosquito Problems
Legal collection does not shield you from trouble if your system causes problems next door. Maine’s surface water statute makes it a nuisance to unreasonably alter the flow of surface water in a way that damages someone else’s property or interferes with their reasonable use of their land.1Maine Legislature. Maine Code Title 17 2808 – Alteration of Surface Water Flow A large system that diverts water away from a shared drainage path or dumps overflow onto a neighbor’s lot can draw a nuisance claim.
Standing water is the other practical concern. Uncovered barrels and tanks turn into mosquito breeding sites fast during Maine’s warm months. Sealed containers or fine mesh screens solve the problem and keep neighbors from complaining. Systems with covered storage, secure plumbing connections, and adequate overflow drainage rarely cause disputes. The owners who end up in trouble are usually the ones who set up a system and then stop paying attention to it.