Best waterless toilet for Narrowboats, widebeams and sailing boats

Whether you’re cruising down a canal or river, or sailing on the open sea, the use of a waterless toilet makes a lot of sense compared to pump-out or ‘elsan’ type chemical toilets – you don’t have to use chemicals, you’re not tied to finding elsan disposal points every couple of days, or face the prospect and costs of travelling to find a pump-out.

In addition, the waterless toilet route gives you a huge degree of autonomy – something many of our customers appreciated when movement and travel was restricted in the recent COVID-19 lockdowns.

What's the difference from a land-based waterless toilet?

The main difference between a land-based waterless toilet and one used on a boat, is that both the liquids (urine) and solids have to be stored on board (separately) until a suitable place is found to dispose or compost them. Liquids can be easily emptied at an Elsan point, toilet, drain or in a convenient hedge (where permitted).

For the solids, depending on the size of your boat, you might have space in lockers, on the roof, or around the engine bay to actually do composting on the go – we know of several ‘continuous cruisers’ on the UK canal network that have compost toilets and compost ‘on the go’ – where there’s a will, there’s a way!

And for people without the space or desire to do the composting themselves, there are even services where companies will take the raw material away for safe composting, and for people with land as well, you can take the ‘waste’ back in secure containers to compost in the usual way.

Special considerations for boats

On boats, urine-separating is the way to go! Many people find that a small urine container, emptied regularly (every day or every other day) is the best approach.  Emptying regularly means the container can be easily swilled out and cleaned.

Below is our recommendations for boats, but some of our other product can be adapted, or you can even make one yourself using the Separett Privy urine-diverter as a starting point!

Our recommendations for the best compost toilets for boats

Separett Tiny with Urine Container


Launched in 2021, the award-winning Separett Tiny is the first toilet from Separett to incorporate a removable urine container, making it ideal for boats.  The Tiny has a very contemporary design and the compact size means it will fit neatly into small spaces. The ventilation system uses 50mm pipework (rigid or flexible) and the fan only consumes around 1.5 watts at 12v DC.

The easily removable urine container has a level sensor that illuminates the Separett logo on the toilet when there’s around 1 -litre of capacity left, letting you know it’s time to empty.

The Tiny doesn’t require any cover material (wood shavings or coir) and simply uses the efficient ventilation system for complete odour removal. An automatic concealing flap (updated and improved in May 2023) means you don’t see into the solids container when you lift the lid – this opens as you sit down and closes as you stand up – automatically.

If required, additional solid and liquid waste containers can be purchased.


Air Head - Standard


The Air Head is the original compost toilet for boats, having been around since 2001. Initially created for ‘weekend-use’ yachts (where the contents will start composting in-situ during the season), it’s also extensively used on narrowboats by both occasional and full-time users.

The Air Head is incredibly tough and durable, and comes with a front-mounted urine bottle for easy emptying. On first use, a rehydrated coir brick is placed inside the solids container – this acts as a carbon-based medium. After each use the handle is turned on the side to mix and aerate the contents. 

A low-power 12-volt fan pulls foul-air out of the toilet through a flexible vent pipe ensuring the Air Head is odour-free and pleasant to use. A manually operated concealing flap covers the opening to the solids container, keeping the contents out of view.

The Air Head can usually provide two adults with 2-3 weeks of solids capacity before it needs to be emptied.

It’s available with either a right-angled or straight fan housing to accommodate a variety of installation situations. If space is really tight, there's a compact seat option which saves 3cm from the overall depth


Build your own boat compost toilet

Whilst the Separett Tiny with Urine Container and the Air Head are the two most obvious choices for boats, there are other options you might consider. Depending on your budget, capacity, skills and aesthetic requirements, you could consider building your own toilet using a urine separator.

Separators, such as the Separett Privy 500 or Privy 501, are an ideal starting point. From that, you can choose suitable containers to hold the solids and liquids. Finally, you’ll think about dealing with odours – you can use a cover material such as coir or wood shavings, or use a fan for forced air extraction – each option has its own merits depending on whether you are aiming for simplicity or sophistication, and to a certain extent, how much work will be involved in the day-to-day maintenance.

Separett Privy 500

£69.95 inc VAT
Separett Privy 501
£99.00 inc VAT

23 Litre Solid Waste Container with lid for Separett Villa

£19.95 inc VAT

It looks like you're in the US.

If you're looking for composting toilets, you should speak to our colleagues in the US instead: