Wastewater Holding Tanks in Caravans, Motorhomes, Mobile Kitchens, Boats

These holding tanks can be for blackwater (toilet), greywater (kitchen, bathroom, shower) or for both combined. They can be very smelly indeed and may produce smells back inside the living/working quarters via the drain hole or from the exterior vent pipe.

In a household situation, grey water for instance is not supposed to be stored for more than 24 hours, otherwise the bacteria present in the water feed on the nutrients (from the soaps, detergents and kitchen wastes) and really can make very bad smells in a relatively short time.

Check that there is no debris, (food scraps in the kitchen drain, hair, soap in the shower drain) and that the u-bend water trap has water in it and the sink or shower drains properly. Ensure that the tank vent pipe is clear and if it has an extension up above the van, that it is fully extended to carry any smells away.

Using Smellgone Odour Control Spray to clean up in your kitchen, bathroom, shower will inoculate the drain lines and the tank itself to help prevent offensive smells.

For blackwater holding tanks or combined black and grey holding tanks also use Smellgone Odour Control Spray.

All Smellgone products mentioned in this article are available in the Wastewater section of our shop.

Caravan Treat (CT)

Where the holding tank is used for more than 24 hours at a time, it is best to inoculate the tank itelf with our Caravan Treatment (CT) at the beginning of the use period and again after emptying it, if you are going to continue using it on that trip. CT contains our hungry bacteria and yeasts along with additional nutrients to get them off to a running start and sustain their activity in what is a 'hostile' environment.

If you routinely use a chemical 'disinfectant' type additive for your holding tank, do not combine it with CT. The chemical disinfectant will kill the beneficial bacteria in CT just as quickly as it kills the other 'bad' bacteria that produce the smells.

Dose rates for CT depend on the size of the holding tank, as a guide, 250 ml is sufficient to treat a 500 litre tank, but should be considered as the minimum dose for any holding tank 500 litres or smaller.