The Rules, Laws, and Benefits of Using a Composting Toilet on a Boat

For many boaters, managing waste is one of the less glamorous but essential aspects of life on the water. The traditional marine sanitation options—such as holding tanks and pump-outs—can be cumbersome and require careful planning. However, there is a growing alternative that is gaining popularity among boat owners: the composting toilet. It offers a more environmentally friendly, hassle-free way to handle onboard waste. In this blog post, we’ll explore the rules, laws, and benefits of using a composting toilet, and we’ll also cover portable toilet options and their use on boats.

Understanding Composting Toilets

A composting toilet is a dry toilet system that processes human waste through aerobic decomposition. Instead of using water to flush waste into a holding tank, composting toilets separate liquids from solids. The solids are mixed with organic materials (such as coconut coir or peat moss) and allowed to decompose naturally. This reduces waste volume and eliminates the need for frequent pump-outs.

Rules and Regulations for Using a Composting Toilet

Before installing a composting toilet on your boat, it’s essential to understand the regulations governing its use, as these may vary depending on your location.

U.S. Coast Guard Requirements: Composting toilets are considered Type III Marine Sanitation Devices (MSDs), which means they are compliant with U.S. Coast Guard regulations for managing human waste on a vessel. They fall under the same category as holding tanks, meaning that the waste is not directly discharged into the water. As long as your composting toilet is sealed and meets all sanitation standards, it is a legal option in U.S. waters.
No-Discharge Zones (NDZs): In no-discharge zones—areas where the discharge of sewage is strictly prohibited—even treated waste must be held onboard. Composting toilets are allowed in these zones because they do not discharge waste directly into the water. Instead, they store the waste in a compostable form, which can then be disposed of responsibly on land.
Waste Disposal: Proper disposal of composted solids is required. Most waste from a composting toilet, once fully composted, is safe to dispose of in regular trash, provided local regulations permit it. The liquid portion, which is urine, can often be diluted and safely disposed of in areas that allow grey water discharge, but regulations for this vary.

It is essential to check the specific requirements in the waters you plan to boat in, as regulations can differ by state, country, or even local jurisdictions.

Benefits of Using a Composting Toilet on a Boat

Composting toilets come with a range of benefits that make them an appealing choice for many boaters:

Environmentally Friendly: Unlike traditional marine heads that flush into holding tanks, composting toilets use no water. This not only conserves water but also eliminates the risk of wastewater spills or leaks, reducing the impact on marine environments.
No Need for Pump-Outs: One of the biggest challenges of using a traditional holding tank system is finding and scheduling pump-outs. With a composting toilet, there’s no need to visit pump-out stations, making your boating trips more flexible, especially when exploring remote areas.
Odor Control: Many people are surprised to learn that composting toilets, when used correctly, are virtually odor-free. By keeping liquids and solids separate, and using ventilation fans, composting toilets control odor much more effectively than holding tanks.
Lower Maintenance: With no plumbing to get clogged and no holding tank to worry about, composting toilets often require less maintenance than traditional systems. The main upkeep involves emptying the urine bottle every few days and occasionally managing the compost solids.
Longer Time Between Empties: Composting toilets can store solid waste for extended periods since the process of decomposition reduces volume. This means you don’t have to worry about emptying the solids very often—making it ideal for extended cruising.

Portable Toilets as an Alternative

For boaters who are looking for a less permanent waste solution, portable toilets (often called “porta-potties”) are another option. Portable toilets are simple, compact units that can be placed in smaller vessels and are particularly popular on boats that don’t have room for a fixed toilet system.

How Portable Toilets Work

A portable toilet consists of two main sections: the upper portion has a toilet bowl and a freshwater tank, while the lower portion holds waste. When flushed, the waste moves into the holding tank, which contains a chemical deodorizer to help manage odor.

When the tank is full, it must be emptied at a designated facility, similar to emptying a holding tank from a traditional marine head.

Rules and Regulations for Portable Toilets

Proper Disposal: It is important to note that the contents of a portable toilet must be disposed of at an approved dumping station. Dumping portable toilet waste overboard is illegal and can result in significant fines. Always ensure you are following local guidelines for disposal.
NDZ Compliance: Portable toilets are allowed in no-discharge zones, provided the waste is not discharged into the water. You must always empty the toilet in accordance with the regulations of the region where you are boating.

Comparing Composting and Portable Toilets

Composting Toilets and Portable Toilets each have their strengths, depending on your boating needs:

Composting Toilets are more suitable for boaters who want a long-term, environmentally friendly waste solution. They require an initial investment and more space for installation, but they eliminate the need for pump-outs and reduce the frequency of waste disposal.
Portable Toilets are ideal for boaters with smaller vessels or those who only spend short periods on their boat. They are easy to install and inexpensive, but require more frequent emptying and require access to proper disposal facilities.

Best Practices for Using Onboard Toilets

Whether you choose a composting toilet or a portable toilet, here are some best practices for managing onboard waste:

Know Your Regulations: Always be aware of the regulations in the area you are boating, especially if you are entering a no-discharge zone.
Minimize Use of Chemicals: With composting toilets, avoid using chemicals that can disrupt the composting process. With portable toilets, use eco-friendly deodorizing chemicals to reduce environmental impact.
Plan Ahead for Disposal: Make sure you know where and how to dispose of waste properly. This might involve locating pump-out stations or understanding where you can legally dispose of composted solids.
Use the Right Material: In composting toilets, use the correct organic material (like coconut coir or peat moss) to ensure proper decomposition. It helps manage odors and speeds up the composting process.

Choosing the right toilet system for your boat depends on your lifestyle and cruising habits. Composting toilets offer a sustainable, low-maintenance solution that eliminates the need for pump-outs and reduces your environmental footprint, making them an excellent choice for extended cruising. Portable toilets provide convenience for short trips and smaller boats, though they require careful planning for waste disposal.

Both options provide legal and environmentally friendly alternatives to traditional marine heads, provided they are used in accordance with local regulations. By choosing a composting or portable toilet and following the proper guidelines, you can make your time on the water more enjoyable while reducing your impact on the marine environment. Happy boating!