Sewage

Preserving Clean Water

What you need to know about sewage before your next outing

On-board sewage management is not a fun thing to think about, but it is a necessary part of your boat’s systems.

Explore the topics via the tabs below to learn more about sewage on the water.

Sewage

The Main Concern: Bacteria & Nutrients

Bacteria can make boating and swimming unsafe and can close waterways and shellfish beds. Excess nutrients can cause algal blooms. Fortunately there are a range of options for on-board sewage management including toilets, holding tanks and even onboard treatment devices. It is important to consider the size of your boat, the type of boating you do, the availability of pumpout stations and if you boat in any No Discharge Zones when selecting the option that is best for you.

There are several options for on-board sewage including:

Composting head
Portapotty
Installed toilet with marine sanitation device

If your boat has an installed toilet by law you must have a Marine Sanitation Device.

Select a Section

The Law Marine Sanitation Devices (MSDs) Pumping Out

The Law

Sewage regulations are some of the most misunderstood boating laws. To be clear, it is ILLEGAL to discharge UNTREATED sewage on inland waters and within 3 miles of shore. To legally dispose of sewage boaters must either have an on-board treatment device (Type I or Type II MSD) or a holding tank (Type III MSD) to hold the waste and have it pumped out ashore. A No Discharge Zone (NDZ) further prohibits the discharge of treated boat sewage.

Within NDZ boundaries, vessel operators are required to retain their sewage discharges on-board for disposal at sea (beyond three miles from shore) or onshore at a pumpout facility.
Vessel sewage discharge is regulated under the Clean Water Act. States can have all or portions of their waters designated as a No Discharge Zone for vessel sewage to:
- Protect aquatic habitats where adequate and reasonably available pumpout or dump station facilities are available for the safe and sanitary removal and treatment of sewage
- Protect special aquatic habitats or species
- Safeguard human health by protecting drinking water intake zones

It is vital to know the locations of any No Discharge Zones in the areas where you are boating. They will be clearly marked on NOAA charts. You can also visit the EPA’s list of No Discharge Zones.

General Tips

When tied up to a dock, use onshore facilities. Encourage guests to take advantage of the onshore restrooms before you set out for a day trip.
Regularly maintain your MSD and the attached plumbing and install the best hose you can afford to reduce odors.
Don’t be afraid to talk about the issue. Talk to your friends and fellow boaters about how to pump out.
Obey the law – keep untreated sewage out of all coastal and inland waters.
Find out if you are boating in a No Discharge Zone do not discharge any sewage, treated or not, in a No Discharge Zone.

Marine Sanitation Devices (MSDs)

Types of MSDs:

Type 1

Type I is a an on-board treatment device using a physical/chemical based system that relies on maceration and chlorination. After treatment the treated waste can be discharged.

Type II

Type II is also an on-board treatment device that uses biological or aerobic digestion based system. After treatment the waste can be discharged. Type II systems are more often seen on large commercial vessels than recreational boats.

Type III

Type III is a holding tank or similar device that prevents the overboard discharge of treated or untreated sewage.

For Type III holding tanks:

Use enzyme deodorizers for holding tanks and portable toilets.
Pump out before you haul your boat for the winter.
Know where your closest pumpout stations are located, and height or draft restrictions, seasonal closures and hours of operation.
Consider using a pumpout boat service if one is offered in your area to make pumping out more convenient.

Pumping Out

If your boat has a holding tank, learning to use a pumpout station is a necessary part of your boat’s operation. This is an area where a small mistake can lead to a big mess, so take your time and be careful.