"NY" wrote in message
...
"Commander Kinsey" wrote in message
newsp.0jfq8biwwdg98l@glass...
I suppose we use what you would call a two pipe system. There is talk
here of introducing a new third pipe for greywater. That is, water that
comes from baths, sinks, showers, etc. as opposed to sewerage from
toilets. Difficult to retrofit of course but new estates are likely to
be plumbed this way in the near future.

My parents have a holiday cottage in a tiny village that has no mains
drainage. All the houses have their own septic tank (two-chamber sewage
treatment unit that does more than just store the sewage, as happens with
a cesspit). However to reduce the amount of water that goes into the
septic tank, all the grey water is piped to a communal "land drain" that
discharges into a nearby stream. I'm sure that arrangement contravenes
almost every health and safety and environmental law known to man!

Do many houses have a rainwater drain in the street?

More than half of ours do. And still do. I have been watching
the installation of services in our new subdivisions, what you
lot call an estate. because a mate of mine is having a new
house built on one.

I thought that usual arrangement was for there to be a soakaway under the
lawn for rainwater,

That is done here when the block is downhill of the
road but not when the house is uphill of the road.
And you can see that on the street view of our
streets. The rainwater pipe into the gutter stands
out like dogs balls if you know what to look for.

so the rainwater and grey/sewage water never mixed.

That's certainly what is legal here, but a few flout the law.

As far as I know, our house doesn't put rainwater into the septic tank,

Yeah, that's a very bad way to do a septic tank.

but pipes it into the same soakaway under the lawn that is used for the
outflow of treated sewage water from the septic tank.

Yeah, that's very common.