Oliver Bennett
Why What You Pour Overboard Matters
Living afloat puts you closer to the water than most people ever get. Your kitchen sink empties into the cut, your shower drain sits a few inches above it, and the same water that carries your grey waste is home to kingfishers, water voles, perch and the occasional curious swan. On a canal or river, that water is slow-moving. A narrow channel with limited flow has very little capacity to dilute what goes into it, so a slug of bleach-based cleaner tipped down the sink in Birmingham can still be doing damage a mile down the towpath. Once you accept that the waterway is effectively your garden, your water butt and your neighbour, choosing gentler products stops feeling like a chore and starts feeling like plain good boating.
What "Biodegradable" Really Means
Not all green-sounding labels are equal. A product described as biodegradable may still take weeks to break down, which is far too slow for a waterway where dilution is minimal. Look for wording that states the product is readily biodegradable or that it meets recognised environmental standards; that indicates the ingredients break down quickly and largely harmlessly in the presence of oxygen and water. Watch out for these common offenders:
- Chlorine bleach — kills micro-organisms indiscriminately, including the microscopic life at the base of the food chain.
- Ammonia — toxic to fish and aquatic invertebrates even at low concentrations.
- Phosphates — trigger algal blooms that strip oxygen from the water when they die off.
- Petroleum-based solvents — slow to degrade, and they leave an oily film on the surface.
- Microplastics and abrasive beads — get eaten by fish and never disappear.
- Triclosan and antibacterial agents — build up in sediment and disrupt wildlife reproduction.
You do not need to memorise a chemistry syllabus. A simple rule works well: if a product carries a hazard warning symbol, treat it as something to use sparingly and never tip overboard.
A Realistic Eco-Friendly Cleaning Kit
You can run a whole boat on a surprisingly short list, and most of it costs pennies. Build a caddy with the following and you will cover nearly every job on board:
- White vinegar — cuts limescale, dissolves soap scum and deodorises. Dilute roughly one part vinegar to three parts water for general wiping.
- Bicarbonate of soda — a gentle abrasive for sinks, hobs and the inside of the fridge. Sprinkle, scrub, rinse.
- Citric acid — brilliant for kettle furring, tap scale and toilet bowls. A tablespoon in warm water goes a long way.
- Castile or vegetable-oil-based liquid soap — the workhorse for floors, worktops and washing up.
- Washing soda crystals — for stubborn grease and for cleaning out the bilge area.
- Plant-based washing-up liquid — check the label says readily biodegradable and phosphate-free.
- Microfibre cloths — clean well with nothing but warm water, which is the greenest option of all.
For the woodwork and paint on a narrowboat, a barely damp microfibre cloth followed by a dry buff often beats any spray. It saves water from your tank too, which matters when the next water point is an hour's cruise away.
Washing Up, Laundry and the Boat Shower
The galley sink is the biggest single source of cleaning chemicals going into the cut, so start there. Scrape plates into the bin rather than rinsing them, use a bowl rather than a running tap, and choose a plant-based washing-up liquid. If you are moored up rather than cruising, use the boatyard's facilities or a washing-up area on the towpath where one exists.
Laundry is the other heavyweight. Traditional detergents are phosphate-rich and heavily perfumed. Switch to a concentrated eco laundry liquid, use the lowest temperature that will do the job, and never run a wash while you are moored in a quiet arm where the water barely moves. On the shower front, a good-quality biodegradable shower gel and a solid shampoo bar will keep your grey water gentler and reduce plastic waste at the same time. If you have a cassette or pump-out toilet, use only the treatment designed for it — home-made alternatives can wreck the seals.
Cleaning the Outside Without Harming the Water
Hull and paintwork cleaning needs care, because run-off goes straight into the cut. A bucket of warm water with a splash of eco wash is usually enough for a week's towpath dust. Avoid acid-based hull cleaners unless you are in a yard with proper containment, and be particularly careful with anything used near the waterline. If you must use a stronger product for blacking or rust treatment, do it ashore on hard standing, never overhanging the water. Deck scrubbing with a stiff brush and plain water removes most green growth, and it keeps your mooring neighbours happy too.
Engine and bilge areas deserve a mention. Oily bilge water should never be pumped overboard. Use absorbent pads under the engine, and clean grubby hands and tools with a plant-based degreaser and a rag rather than a solvent spray.
Small Habits That Add Up
Products matter, but habits matter more. Buy concentrates and dilute them on board, which cuts plastic and weight. Refill bottles at zero-waste shops in towns along the cut where you can. Store everything in a sealed crate so nothing tips into the bilge in a lock. And remember that the canal network is a shared home — the heron you watched this morning is drinking the same water that leaves your sink. A few thoughtful swaps in your cleaning caddy are one of the easiest, cheapest ways to be a good neighbour to it.
