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Rainwater filters

Water filter for water coming from rainwater well

Water filterin the garage or storage room

Replacing tap water with rainwater

Of the 120l per day that the average Flemish person uses daily, it is not necessary to use drinking water about half of the time and you can perfectly use it instead of city water. 

You can use the rainwater you collect:

       - To flush toilets (33l per day)
       - For the washing machine or for hand washing (15l per day)
       - Watering flowers, plants or your garden (5l per day)
       - For cleaning (6l per day)
       - Car wash
       - Etc...


Most common problems

It is important to know that the rainwater tank is primarily a collection container for bacteria – just think of those bacteria from bird droppings that inevitably end up on everyone's roof.

In addition to the request to disinfect rainwater, we most often receive questions about a solution for unpleasant odors and yellow discoloration of the rainwater. Both can be very disruptive when using rainwater for, for example, the washing machine.

Sand, dirt and dust on your roof flow with the water into the rainwater tank when it rains. That sludge sinks to the bottom of your rainwater tank, so that the clearest water is at the top of your tank, and at the bottom of the tank there is a layer of sludge with less pure rainwater.

In most rainwater tanks, the fresh, oxygen-rich rainwater flows into the top of the tank and is then sucked up again at the bottom, where most of the dirt is located, with a pump on the floor of the tank. The pump sucks up the oxygen-poor and polluted water and sends it to the tapping points in the house. As a result, the pre-filters, which filter sand and other impurities from the water, have a hard time and often have to be replaced and/or maintained.

Bulky waste filter (photo 1)

A coarse dirt filter is usually located in the rainwater well and retains the coarse pieces of dirt (leaves, branches).
Check this filter regularly so that it does not become clogged or that a layer of biofilm forms on it that blocks the passage. 

Sediment filter (photo 2)

The pre-filter is usually located in the garage at the point where rainwater enters your house.

Because sand and silt from your roof always come with the rainwater, it is necessary to install a sediment filter between the rainwater tank and the rainwater taps in your house.

This type of pre-filter filters small, floating particles (e.g. sand, dust, etc.) from the rainwater. 
You replace sediment filters once or twice a year, depending on the region (sandy or not) where you live.

Activated carbon filter (photo at 2 and 3) black filter

Very often a sediment filter is combined with an activated carbon filter.

Activated carbon ensures that your rainwater remains clear (removes discolorations) and that it does not smell bad. 

Activated carbon is a specially treated carbon that can bind all kinds of substances through adsorption. An important area of application is filtering.

Activated carbon is prepared by removing the gases and impurities through a thermal process. Coking coal, i.e. with coal as a starting product, produces the highest quality of activated carbon, i.e. with the highest adsorption capacity for the same quantity. It is also the most expensive form of activated carbon. Cheaper starting products with less adsorption capacity are brown coal coke and organic material such as peat or coconut shells.

Just like a pre-filter, the filter fleece must also be replaced at least once a year. If the water is very dirty, replace the fleece as often as necessary. For hygienic reasons, the activated carbon must be replaced every 6 months. 

UV filter (photo at  4 and 5)

A triple pre-filter is the solution for complete rainwater purification: 

In addition to the sediment filter and the activated carbon filter, a sterilization module with ultraviolet light is added.
This water disinfection technology is very environmentally friendly.

“These triple filters are particularly popular because they remove 99.9% of microbes, bacteria, viruses and protozoa.”

Perfect for disinfecting water. 

The maintenance schedule of this triple filter is as follows: 

- Sediment filter: every other year or more frequently if necessary
- Activated carbon filter: every 6 months
- UV lamp: every other year

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