Camper van toilet: chemical, composting or cassette?

There are three common types of toilets for camper vans:

Chemical toilet (portable, e.g. Porta Potti)A compact, portable unit with a flush water tank on top and a waste tank below. Uses chemical fluid to suppress odour and break down waste. Price: €60-€150. Weight: 3-5 kg empty.

Cassette toilet (permanently installed)A fixed-mount toilet with a removable cassette (waste tank) that you access via an external hatch. Same principle as chemical, but more comfortable due to fixed seat height. Price: €200-€500. Weight: 5-10 kg.

Composting toilet (separation toilet)Separates urine and solids. Solids are covered with wood shavings or coconut fibre and dry out (compost). No chemicals needed. Price: €150-€800 (e.g. Trobolo, Trelino, Nature's Head). Weight: 5-15 kg.

Chemical / cassette:✓ Familiar system, simple to use✓ Cheap to buy (portable)✓ Flush water keeps it clean✗ Chemicals needed (€5-€10 per refill)✗ Emptying only at special dump points (not in a regular toilet)✗ Odour can be a problem in warm weather✗ Regular emptying needed (every 3-5 days for 2 people)

Composting toilet:✓ No chemicals needed✓ Urine can be disposed of in a regular toilet or in nature✓ Solids can go with household waste or be composted✓ Less frequent emptying (solids every 2-4 weeks)✓ No water needed = lighter and simpler✗ More expensive to buy✗ Fan needed for odour control (small, 0.1-0.3A)✗ Getting used to the separation principle✗ Wood shavings/coconut fibre need refilling

Space: a portable chemical toilet fits in a cabinet of 40×40×45 cm. A fixed cassette or composting toilet requires a dedicated bathroom space or a creative solution (under the bed, behind a curtain).

Water usage: a chemical/cassette toilet uses 0.5-1 litre of flush water per use. At 4 times per day for 2 people, that's 4-8 litres per day — a significant drain on your water supply. Composting toilets use no water.

Vehicle inspection: a toilet is not required for camper van registration (SA classification). You don't need one to pass inspection.

Waste water: if you have a cassette toilet, the flush water (grey water) must be collected separately. This means an additional tank that takes up space and weight.

Odour: for composting toilets, a small fan (12V, 0.1-0.3A) is essential that continuously blows air over the composting chamber and vents it outside via a hose. Without the fan, it can smell.

Choose based on your travel pattern:

Weekend use or occasional off-grid: a portable chemical toilet (Porta Potti) is the simplest and cheapest solution. Store it in a cabinet when not in use.

Long-term travel, lots of off-grid: a composting toilet is the best choice. No water needed, less frequent emptying, no chemicals. The higher purchase price pays for itself through lower running costs.

Maximum comfort: a fixed cassette toilet with a dedicated bathroom space. Closest to a home toilet, but takes the most space and weight.

No toilet at all: many camper van builders choose not to install a toilet and use public facilities, nature (with a trowel) or an emergency bucket. This saves space, weight and money, but isn't ideal at night or in bad weather.

Tip: start with a cheap portable chemical toilet (€60-€80) to test whether you really need a toilet in the camper, before investing in a more expensive fixed system.

A flushing toilet lives off the same tank as your shower and your coffee. In a camper where water is the limiting factor, that counts.

The water calculator works with 1 litre per flush and four flushes per person per day. With two people that is 8 litres over 24 hours. On a fresh water tank of 80 litres that is a tenth of your supply, every day.

Set that against the rest of your use: a shower costs 20 litres per person, hand washing 9 litres per person per day, washing up 10 litres for the whole van. So the toilet is not your biggest item, but it is one you can strike out.

A dry separating toilet uses no water at all. With two people that saves 8 litres a day. On a frugal usage pattern and an 80 litre tank your autonomy goes from 2.5 to 3.4 days, almost a day more. That is usually the real argument for such a toilet, more so than the smell.

Do not forget that what goes in has to come out. A flushing toilet fills its waste tank faster than your fresh tank empties, because urine is added to it.

The point at which people regret their choice is rarely during use and almost always at emptying.

A cassette toilet is emptied at a disposal point, at a campsite or at a motorway service area. In the Netherlands and Germany those sit reasonably close together; in southern Europe and out of season they are further apart than you expect. An ordinary toilet is fine too, provided it is on mains drainage and you use no chemistry that does not belong there.

Emptying a dry separating toilet works differently. The urine bottle goes into an ordinary toilet and can go anywhere. The solids, with wood fibre or coco coir in them, go into a sealed bag with general waste; it is not compost until it has genuinely composted for months.

The rule of thumb for frequency:

• A 17 litre cassette, two people: every three to four days
• A urine bottle of 5 to 10 litres: daily to every other day
• The solids of a dry separating toilet, two people: every one to two weeks

That urine bottle is the deciding measure in practice. Plan around it, not around the tidy week the brochure quotes.

The unpleasant smell in a camper toilet nearly always arises at the same moment: when urine and solids come together. Kept apart, both are remarkably odourless.

That is the entire idea behind a dry separating toilet. At the front sits a funnel for urine, at the back a container with wood fibre or coco coir. If the separation works, you smell nothing in the van. If it does not, because the seating position is off or the funnel is too small, you have a bucket of wet fibre and you certainly do smell it.

With a cassette toilet you solve it with an additive in the cassette. Choose an enzyme-based product rather than a formaldehyde one: many disposal points no longer allow the latter into the drains, and it has a smell of its own.

What helps in both cases:

• A vent from the cassette or container to the outside, not to the inside
• Being able to ventilate the space the toilet sits in
• Not leaving emptying too long, because the smell comes with time

This is also why the toilet rarely has to sit against an outer wall: a short vent hose weighs more than the location does.

In a compact van the toilet competes with your kitchen and your seating. The floor space you need for it is about 40 by 40 cm, which is exactly what the layout tool reserves for it.

What works in a small van:

• A portable toilet under the bench or under the bed, brought out only when needed
• A toilet inside the shower space, so the same square metre does two jobs
• A pull-out drawer holding the toilet that you slide shut when you are done

What rarely works: a separate toilet compartment in a van shorter than six metres. It costs you half a metre of length you cannot find anywhere else.

Think about height. A dry separating toilet often builds taller than a cassette one, because a container has to fit underneath. If you are in a van with a raised floor over the wheel arches, measure whether you still sit comfortably on it before you build the cabinet.