How to empty grey and black water, the right order, which products to use and the mistakes to avoid. Everything you need to do it cleanly and without surprises.
Emptying the tanks is the least glamorous task of the trip, but doing it well makes the difference between a pleasant motorhome and one that smells. Here is the full process, step by step.
What each water is
- Grey water: what comes from the sink and the shower. It carries soap and food scraps but no toilet waste.
- Black water: from the toilet. Depending on the vehicle, it goes to a fixed tank or to a removable cassette.
Both kinds are emptied at proper points. Never in the street, in the countryside, in a drain or in a river, however convenient it may seem.
Before you start
Put on gloves and have a clean-water hose that you use only for this. Check that the disposal point is for motorhomes and that it is available. If there is a queue, wait your turn.
Black water, step by step
- Position the vehicle so the outlet is close to the drain.
- If your toilet has a cassette, take it out and carry it to the cassette drain. If it has a tank, connect the disposal hose.
- Open the outlet slowly and let the tank empty completely.
- Rinse with clean water several times until it runs clear.
- Add a sanitary product for the tank (biodegradable versions exist) and some water before using the toilet again.
Grey water, step by step
- With the outlet connected to the drain, open the grey tank valve.
- Let it empty entirely. Grey water, being soapy, helps rinse the hose.
- Close the valve and disconnect.
The order matters
Empty the black water first and the grey water after. That way the soapy water flushes whatever is left in the hose and the drain.
After emptying
Rinse the hose and store it in a separate compartment, never with the drinking-water one. Wash your hands. If you used chemical products, check that they are suitable for the system at your stop.
Common mistakes
- Emptying outside an authorised point: the most serious mistake. It pollutes and is usually fined.
- Forgetting to rinse: it leaves smells and blockages.
- Mixing hoses: use one for drinking water and another for disposal, and tell them apart by colour.
- Waiting until the tank is at its limit: empty earlier, for comfort and to avoid spills.
How Parkvan helps
On Parkvan you can see the dump points around each stop and the ones other travellers recommend, so you can plan emptying into your route.
