In urban areas, the pipes that collect rainwater from your
roof and yard are connected to a network of underground
pipes that transfer the rainwater to local streams or to the
seashore. These pipes are the stormwater system. There is
a separate system of pipes that transfer wastewater from
the toilet, bathroom, kitchen, and laundry to a sewage
treatment plant. These pipes are the sewerage system.
In areas without stormwater systems, rainwater from roofs
and driveways may drain into soak holes. In areas without
sewerage systems, wastewater is generally treated in a
septic tank.
It is illegal for stormwater to go into sewers. It is illegal
for anything other than rainwater to go into stormwater
drains. If wastewater or other liquid household wastes (see
table over the page) get into the stormwater drain, they will
pollute streams, aquifers or the sea.