How to clean the grey water tank in your motorhome and stop bad smells

Why does the grey water tank start to smell?

Grey water comes from washing dishes, washing and showering. Although it contains no faecal matter, it carries food residue, grease, soap, shampoo, toothpaste and other organic substances into the tank. Some of this residue clings to the pipes, drains and the inner surfaces of the tank.

Simply emptying the tank therefore often doesn't remove everything left in the system. Deposits form on the inner walls and in hard-to-reach spots, creating an environment where bacteria thrive. The result is unpleasant odours that travel back through the drains into the living space.

The problem is more noticeable in warm weather, during longer periods of standing still, or when wastewater stays in the tank for a long time. While driving, the contents slosh around inside the tank, making the smell even stronger. Regular emptying is important, but it's worth complementing it with preventive care of the system.

How do you correctly use FRESH TANK in the grey water tank?

FRESH TANK is a product for neutralising unpleasant odours in grey water and wastewater tanks. It's used when you notice a bad smell from the drain or tank, and it's equally suitable for preventive use.

When a bad smell appears, pour at least 200 ml of the product directly into the drain, for example the sink drain. The product travels through the drainpipes to the tank and starts working in the system. According to the label instructions, the odour typically breaks down within around 15 to 60 minutes.

If the smell isn't sufficiently reduced, add more of the product. The amount needed depends on the volume of water in the tank and the intensity of the odour. For preventive use, dose the product in good time – before a longer trip, in hot weather, or when the motorhome will be parked in the same spot for several days.

How do you clean the grey water tank and reduce build-up?

For good system care, first empty the tank at a designated service point. Then, if possible, rinse it with clean water to remove fresh residue.

Pour an appropriate amount of FRESH TANK into the drain. This way, the product reaches not only the tank but also the pipes through which wastewater drains from the kitchen sink, washbasin or shower.

The best results come from combining regular emptying, rinsing and preventive use of the product. FRESH TANK is suitable for plastic and stainless steel, but it can cause corrosion on iron surfaces, so always check the materials in your system and follow the instructions on the packaging.

How do you prevent bad smells before they start?

You can achieve the most through everyday habits. Before washing up, remove larger food scraps from plates, and don't pour oil, grease, sauces or coffee grounds down the drain. This residue clings to pipes and the tank walls, speeding up the formation of odours.

Empty the tank regularly and don't leave wastewater in it longer than necessary, especially in summer. When the motorhome or caravan stands in one place for several days, check the state of the grey water tank more often.

You can add FRESH TANK preventively, before the first bad smell appears. This makes sense before a longer trip, during hot spells, when the kitchen and shower are used more intensively, or when water will remain in the tank for a longer period.

Key takeaways

• The grey water tank collects wastewater from the kitchen sink, washbasin and shower.
• FRESH TANK neutralises unpleasant odours in grey water and wastewater tanks.
• It's used when a smell appears or preventively.
• When a smell appears, pour at least 200 ml directly into the drain; the odour typically breaks down within 15 to 60 minutes.
• Regular emptying, rinsing and limiting food and grease in the drains keep the system fresh.