Let's talk about the topic nobody brings up at dinner parties but every narrowboat owner thinks about: toilets. Your narrowboat toilet is one of the most important systems on board, and choosing the right one can make a real difference to your cruising comfort and your maintenance workload.
Whether you're fitting out a new boat, upgrading an existing system, or just trying to figure out what you've inherited, this guide covers every narrowboat toilet option — with honest pros, cons, and real costs.
The Three Main Narrowboat Toilet Options
There are three types of toilet system commonly used on canal boats in the UK: pump-out, cassette, and composting. Each has its place, and the best choice depends on your cruising style, budget, and how much DIY you're comfortable with.
Pump-Out Toilets
A pump-out toilet works much like a household toilet. You flush with water, and waste goes into a large holding tank (typically 50-100 gallons) built into the boat. When the tank is full, you take the boat to a pump-out station where the tank is emptied using a suction pump.
How Pump-Out Works
The toilet itself looks and feels the most like a domestic loo. You push a pedal or button to flush, water carries the waste into the holding tank, and you carry on with your day. When the tank fills up — usually every 2-4 weeks for a couple — you visit a pump-out station.
Pump-out stations are found at marinas, boatyards, and some Canal & River Trust service points. The process takes about 10 minutes and costs £15-25 per pump-out, though some marinas include it in mooring fees.
Pump-Out Pros
- Most like a home toilet — comfortable and familiar
- Large tank means less frequent emptying
- No handling of waste — the pump-out machine does it all
- Good for families and liveaboards who want convenience
Pump-Out Cons
- Dependent on pump-out stations — can be inconvenient on remote stretches
- Tank can smell in hot weather if not treated with chemicals
- Installation is more complex (built-in tank)
- Pump-out costs add up: roughly £300-600 per year for a liveaboard couple
- If the pump fails, you've got a problem
Pump-Out Costs
- Toilet unit: £200-800 depending on the model
- Holding tank and installation: often built into the boat shell
- Per pump-out: £15-25
- Annual chemicals: £30-60
Cassette Toilets
A cassette toilet has a small removable waste tank (the cassette) that slides out from under the toilet, usually accessed via a hatch on the outside of the boat. When it's full, you carry it to an Elsan disposal point and empty it.
How Cassette Toilets Work
The toilet has a small built-in flush using a freshwater reservoir. Waste drops into the cassette below, which typically holds 18-21 litres. A sliding blade seals the cassette when not in use. When the indicator shows full, you pull the cassette out, wheel or carry it to an Elsan point, empty it, rinse, and slide it back in.
Cassette Toilet Pros
- No dependency on pump-out stations — Elsan points are everywhere
- Cheaper to buy and install than pump-out systems
- Self-contained — easy to retrofit into any boat
- Elsan disposal is free at CRT sanitary stations
Cassette Toilet Cons
- Small tank means frequent emptying — every 2-4 days for a couple
- You have to carry and empty the cassette yourself (not glamorous)
- The cassette is heavy when full (around 20kg)
- Chemical costs are ongoing
- Can smell if not maintained well
Cassette Toilet Costs
- Toilet unit (e.g., Thetford C200/C400): £150-500
- Annual chemicals: £50-80
- Replacement cassettes: £60-100
Composting Toilets for Narrowboats
Composting toilets have become hugely popular with narrowboaters in recent years, and for good reason. They separate liquid and solid waste, use no water for flushing, and produce compost rather than sewage.
How Composting Toilets Work
A composting toilet uses a urine diverter at the front of the bowl to separate liquids from solids. Solid waste drops into a chamber below, where a covering material (coconut coir, sawdust, or wood shavings) is added after each use. A small fan draws air through the system, keeping things aerobic and odour-free. Urine goes into a separate container.
The solids bin needs emptying every 3-6 weeks for a couple (longer for solo boaters). The urine bottle needs emptying every day or two. Solid waste can be double-bagged and disposed of in regular bins, or composted if you have access to a suitable site.
Best Composting Toilets for Narrowboats
The most popular composting toilets in the narrowboat community include:
- Nature's Head — the most common choice. Robust, well-designed, with a built-in agitator. Around £900-1,000.
- Air Head — similar to Nature's Head with a slightly different design. Around £900-1,000.
- Separett Villa / Tiny — Swedish-made, urine-diverting. The Tiny model is popular for smaller boats. Around £600-900.
- DIY builds — many boaters build their own using a urine separator and a bucket. Costs as little as £50-100.
Composting Toilet Pros
- No water needed for flushing — saves your freshwater tank
- No pump-out stations needed — true self-sufficiency
- Virtually odour-free when working correctly (many boaters say they smell less than pump-out or cassette systems)
- Environmentally friendly — no chemicals, no sewage
- Simple to install — just needs a 12V connection for the fan and a vent hose
- Low running costs
Composting Toilet Cons
- Higher upfront cost for commercial units
- Urine bottle needs daily emptying
- Takes some getting used to — the "add material after each use" routine
- You need to source covering material (coconut coir is popular and compact)
- Disposal of solids is a grey area — technically it should go to landfill, not in hedgerows
- Guests sometimes find them unfamiliar
Composting Toilet Costs
- Commercial unit: £600-1,000
- DIY build: £50-150
- Annual running costs (coir, bags): £20-40
- Replacement fan: £15-30 every few years
Elsan Points and Pump-Out Stations: Where to Empty
Whatever toilet system you choose, you'll need somewhere to dispose of waste:
- Elsan disposal points are found at most CRT service blocks and many marinas. They're free to use and accept cassette waste and composting toilet urine. There are hundreds across the network.
- Pump-out stations are less common but found at most marinas and boatyards, plus some CRT sites. Expect to pay £15-25 per pump-out. A few have self-service machines.
Which Narrowboat Toilet Is Right for You?
Here's a quick decision guide:
- Choose pump-out if you want maximum home comfort, don't mind visiting pump-out stations, and have the budget for ongoing costs.
- Choose cassette if you want a low-cost, flexible option and don't mind frequent emptying. Great for occasional-use boats.
- Choose composting if you value self-sufficiency, want low running costs, and are happy to learn a slightly different routine. The favourite of most liveaboards and continuous cruisers.
Find Pump-Out Stations and Elsan Points
Need to find the nearest place to empty your tank or cassette? Use our directory to search for pump-out stations and Elsan disposal points across the UK canal network.