Last week while it was raining (typical Belgian summer) I was thinking "I'm happy our house seems leak free and without troubles"
. Not much after we had water in the garage after $CHILD took a bath. Water and foam everywhere in the garage and in the semi-cellar.
We put some chemicals in and hoped that this would work. It did not. A few days later at dinner a heard a noise and a bit later water was rising in the garage.
Calling the really nice ex-owner we discovered that the 'brown water' from the toilet goes into a septic tank
from there it goes into a trap
together with the 'grey water' (kitchen, bathroom and rain water). He told us the problem is most likely a blockage in that trap
as it also has a filter to keep the animals out.
He helpfully also told us it was in our front garden. 1 meter (~ 3 feet) down.
So we dug in the mud and found it. On my belly in the mud with my head in the hole I opened the inspection lid. 'Water' came out in a jet, with the liquid rising rapidly I just managed to close the cover before it reached me.
This was the moment I called in the professionals. Who told me that they needed access to the trap and septic tank. So over the weekend I dug a hole 1.5 by 1 by 1 meter in our front garden. By then the level of water had gone down so I could already remove most of the junk from the trap. It was mostly soap, hair and other small waste.
On Monday the specialists came with a trunk-powered liquid vacuum cleaner, sucking out the trap and the septic tank. The friendly guy also told me of the existence of extension tubes so that you can clean the trap every few months. Something that I will do religiously from now on....