Bad smells in my rainwater tank, what should I do? Rainwater that stinks...

Bad smells in my rainwater tank, what should I do? Rainwater that stinks... This is a question frequently asked to our Foudebassin experts.

How to fight bad odors?

• Act at the source (directly in the tank)
• Installed rainwater filters near the hydrophore group.

After a few years of operation, rainwater can start to smell bad if the tank does not have aeration or specific bacteria on a regular basis. This can be a very tricky problem, especially if you use this water for laundry.

The appearance of odours often occurs after a warm period during which rainwater consumption has been reduced (often the case during holidays).

These bacteria are found in natural environments. However, in too great a number and with heat, a significant deposit on the bottom and stagnant water, these bacteria will produce an unpleasant odor (eutrophication of the tank).

Some specific situations can explain these olfactory problems of the rainwater tank: excess pollen in the water, organic waste from birds, little pumping in the tank (stagnant water), decomposing leaves and many trees nearby. In certain situations (layers of more than 10CM of dirt in the bottom of the tank) and a tank that has never been maintained, a complete maintenance and emptying may be necessary. Our experts can empty your rainwater tank.

In any case, it is important to limit the amount of organic waste in the rainwater tank. The presence of a suitable and well-maintained filter on the network that carries rainwater to the tank is essential. However, if you did not have a pre-filter, consider providing an air pump and long-term treatment . You can also add filters between your tank and your house.

Why does the water in my rainwater tank give off bad smells?

There are three factors that cause bad odors to be released:

• the light
• the heat
• organic waste (roofs, gutters, etc.)

Beware of deposits that accumulate on the bottom. These organic wastes will form a layer on the bottom of the tank. When you smell odors, it is often because of anaerobic bacteria that cause fermentation on the bottom (releasing a sulfur or sewage odor).

There is also the area where the water is sucked in, we advise you to provide a float with a non-return valve fixed to the suction pipe. We offer kits adapted to the diameter of your pipe to suck up water on the surface. This water is often of better quality for your toilets and showers.

How do I treat bad odors from my rainwater tank?

At the time, and at the beginning of rainwater tanks, bleach was recommended. This treats the problem in the short term, to improve the quality of the water:

• an air pump for rainwater tank
• a chlorine-free treatment based on bacteria ( bactorain type )

Bleach works in the very very short term and will even kill the natural bacterial environment. One of the solutions recommended by rainwater tank experts is the installation of an aeration system. No more odors and the yellowish color of the water. These odors are emitted by anaerobic bacteria and they hate oxygen in the water.

What preventive solutions are there for odors?

The first precaution if you have never thought about cleaning your rainwater tank is to clean the gutters and roofs.

Your tank must also be at least minimally protected from temperature rises. If you are only at the idea stage, we recommend an underground tank. For an excellent result, reducing odors and improving water quality, you can use a specific air pump (it is similar to what you find in aquariums but larger).

Is rainwater harmful?

The bacteriological quality of rainwater can sometimes be very poor and cannot, in any case, be compared to that of drinking water. It is water that is not treated as in a catchment station, moreover it contains very few minerals unlike tap water which comes from springs.

This is why rainwater can only be used for non-sanitary applications and never in cooking.