Has the warm weather welcomed a monster into your grey water tanks?

July 10, 2019

At this time of the year, we receive emails from many clients to say their grey water tanks are suddenly emitting a nasty niff and it is really difficult to live with in a motorhome! The problem is simply the rise in temperature and as a general rule, the hotter it is, the more quickly your grey water tanks will become smelly if you don’t disinfect them.

There are all sorts of extortionately expensive, specialist products you can buy to overcome the problem but we think good old bleach is the most effective way to treat this problem. Here’s the way we go about using bleach and some other tips to stop bacteria from building up and creating a bad smell:

1) Empty grey tanks completely then close the valve.

2) Buy some thick bleach (in France it is called “Javel Precisé”), tip around half a cup down every plughole (kitchen, hand basin and shower) and leave it for about an hour then rinse it through into the tank fully with a few litres of water in each basin/shower tray and just cock open the grey tank for a second so the bleachy water is pulled right through the system but there is plenty still in the tank. Now leave it for as long as you can (minimum a few hours but all day if you can) then simply empty it and flush the tanks through with clean water. If you happen to be driving about with the bleachy water in the tank, that really helps to clean it as it effectively washes the entire tank as it sloshes about.

Important Note: Be VERY careful not to splash bleach on your clothes or the upholstery in the van – it will ruin any fabric it comes into contact with.

That should work but some for years before we tried bleach, we used cheap cola to detox the tanks on our rental fleet and that was generally successful too. If you use cola, leave it in the tank overnight and buy sugar-free as it does not leave a sticky mess if you accidentally splash it as you pour.

To avoid the problem, our advice is to tip as little organic matter or grease as possible down your sink to avoid bacteria building up. Your waste tanks will quickly become smelly if you throw stuff like coffee grounds, milk, oil or pretty much anything other than water and cleaning chemicals into your tank. You should also empty your grey tanks as frequently as possible during warmer weather to stop bacteria getting out of control.

If you have a motorhome problem you don’t know how to solve, get in touch so we can share our solution with you and others in our blog. If you are an old hand and have some good tips to share, do please let us have those too.