Watering the garden- environmental dilemma

In Belgium grey water systems are in all new-builds. Yes, each building has a retaining tank under the building/patio, to hold its own grey and rain water. This is then used for garden watering, toilet-flushing, etc. Our house is older than this regulation, but we have a rainwater tank under the patio (probably needed for the extension plans to be approved). So our tank is just rainwater, rather than combined.
Two years ago we were partially connected to the mains sewage. I say “partially”, as solids are held in the existing septic tank, and liquids join the street sewage system. We have to separate rain water from this. Two separate pipe systems were set into the street, one to take away rain water, one for “dirty” water. We had to prove that rainwater does not go into the sewage system. This had to be done to comply with EU regulations…. This is a retrospective installation. Most of the houses on the street are 40 years old. So it is possible to do!!

 

@Sian in Belgium What happens when the grey water tank is full, how do you dispose of it if you are creating more than you reuse.

 

As far as I know, there is a system of soakaway into the ground (as with a septic tank), or it goes into the grey/rainwater pipes in the street.
I am no expert on the general technicalities, but I know what happens in this older-housing street, and for a newer build property with its own grey water tank.

 

Bearing in mind the water companies cant even keep up with fixing leaks I doubt any such system could be brought in over here for anything other than new builds.

 

In my last house in Nottinghamshire, I tried asking the local authorities if I could put in a grey water capture tank in the ground - they were totally negative about it, so all I did was have water butts on every corner of the house. It annoyed me because I had a septic tank anyway, so it wouldn't have changed anything elsewhere. BTW, septic tanks force you to think carefully about not wasting too much water from your house - you don't want them filling up!

 

Sorry, the penny has dropped! Fat bergs ... grease icebergs.

When I said I don't like grease on my hands, I didn't mean like car grease (I used to work on cars, do my own maintenance up to and including changing a head gasket) ... it is kitchen grease I can't stand, cringe!!!