Boat sewage and pump-outs

Sewage from boats is a small part of the pollution in our waterways, but in sheltered bays, rivers and marinas it can matter a lot. It adds nutrients and bacteria, can close oyster leases and swimming spots, and is unpleasant for everyone. That's why states regulate where and how boats can discharge sewage, and why marinas and boat ramps increasingly have pump-out stations. This guide explains the main options for managing sewage on board and, using Queensland's rules as a worked example, how discharge limits work. Rules differ between states, so check your own.

Three ways to manage sewage on board

Maritime Safety Queensland describes the main alternatives for boaters:

1. A holding tank, which stores sewage on board for later disposal ashore at a pump-out facility, or in open waters where discharge is permitted.
2. An onboard treatment system, which treats sewage to a certified standard before discharge.
3. A portable toilet, which you empty at an onshore dump point.

Many small boats have no toilet at all, in which case the rules mainly apply to what you do with any portable toilet. Larger boats usually have a marine toilet connected to a holding tank, a treatment system, or both.

How discharge limits work: the Queensland example

Queensland's rules are set out in the Transport Operations (Marine Pollution) Act 1995 and the Transport Operations (Marine Pollution) Regulation 2018. They describe nil discharge waters: places where discharging sewage isn't permitted. What applies depends on whether the sewage is treated or untreated, and on the type of vessel.

Untreated sewage

For most recreational boats, the waters where untreated sewage must not be discharged include:

• prohibited discharge waters;
• smooth waters, which MSQ says include rivers, creeks, streams and lakes, and the waters within breakwaters or revetments, so most marinas;
• waters within one nautical mile (1,852 metres) of a person in the water, aquaculture fisheries resources such as an oyster lease, or a reef.

The 2018 regulation also made clear that discharging untreated sewage within one nautical mile of the mean low water mark of an island or the mainland is prohibited. In practice, that means untreated sewage can only be released well offshore, and a holding tank is the practical solution for most boats in sheltered waters.

Treated sewage

MSQ recognises three grades of treated sewage from certified treatment systems:

• Grade A treated sewage can be discharged anywhere except prohibited discharge waters.
• Grade B can be discharged outside prohibited discharge waters more than 700 metres from sensitive areas.
• Grade C, the lowest level of treatment, can be discharged outside prohibited discharge waters more than half a nautical mile (926 metres) from sensitive areas.

In this context, MSQ lists sensitive areas as a person in the water, aquaculture fisheries resources such as an oyster lease, and a reef.

Larger vessels

Some vessels, called declared ships, have stricter rules, including a requirement to be fitted with a sewage holding device to operate in nil discharge waters. If your vessel is large or carries many people, check MSQ's definitions or ask your regional office.

Other states

Every state and territory has its own sewage rules, and some waterways have extra restrictions, such as no-discharge zones in lakes, rivers and marine parks. Before you travel, check your state maritime authority's website for sewage rules and pump-out locations. A good rule of thumb is to assume you can't discharge untreated sewage in any enclosed or sheltered water, and plan to use a pump-out.

Using a pump-out

Pump-out stations are usually at marinas, fuel docks and some public jetties. MSQ publishes a list of pump-out facilities around Queensland, and other states do the same.

A typical pump-out:

1. Berth alongside the pump-out station, securely moored.
2. Read the instructions; some stations need a card, token or switch.
3. Open your holding tank's deck fitting, often marked "waste". Make sure it isn't the fuel or water filler.
4. Insert the pump-out nozzle firmly into the fitting and start the pump.
5. When the tank is empty, many owners rinse it by adding some fresh water through the toilet and pumping again.
6. Turn off the pump, remove the nozzle, rinse it if the station allows, and replace your deck cap.
7. Leave the station clean for the next person.

Wear gloves, keep the nozzle pointed into the fitting, and wash your hands afterwards.

Holding tank care

• Know your tank's size and how quickly it fills with your usual crew.
• Use marine toilet paper or paper that breaks down easily, and never flush wipes, sanitary products or anything else that can block the system.
• Keep vents clear; a blocked vent can cause smells and pressure problems.
• Use treatments designed for marine holding tanks if needed.
• Check hoses and fittings for leaks and smells, and replace tired hoses.

Grey water and other waste

Grey water from sinks and showers, bilge water, rubbish and oily waste have their own rules. Don't pump oily bilge water overboard; use absorbent pads and dispose of them ashore. Take all rubbish home or use marina bins. Agriculture Victoria also notes that sewage and bilge tanks are niche areas where marine pests can accumulate on moored boats, another reason to keep them clean.

Portable toilets

Portable toilets are common on smaller boats. They hold waste in a sealed tank that you carry ashore and empty at a dump point designed for the purpose, such as those at many marinas, caravan parks and some boat ramps. Never empty a portable toilet into the water or a stormwater drain. Secure the toilet so it can't tip over under way, keep the seals in good condition, and rinse it after emptying.

Planning a trip around pump-outs

Before a longer trip, look up where the pump-outs are along your route and how long your holding tank lasts with your usual crew. Pump out before you leave and whenever you pass a convenient station, rather than waiting until the tank is full. Some pump-outs close for maintenance or have limited hours, so it's worth having a backup. If you'll be in remote areas, find out where discharge is permitted under your state's rules before you go, and keep a note of the rules on board.

Fitting or upgrading a system

If your boat has a toilet that discharges straight overboard, consider fitting a holding tank or a certified treatment system. A marine plumber or boatbuilder can advise on tank size, placement, vents, deck fittings and hoses. Check your state's requirements first, because some rules depend on the type of system and the vessel.

Key points

• Use a holding tank, a certified treatment system or a portable toilet.
• In Queensland, untreated sewage can't be discharged in smooth waters, including inside breakwaters, rivers and creeks.
• Queensland's buffers: one nautical mile for untreated sewage, 926 metres for Grade C, 700 metres for Grade B.
• Rules differ between states; check before you travel.
• Plan to use pump-outs, and look after your holding tank.