Why this matters for the Dart: a single misconnected washing machine can pour its dirty water into a Dart tributary for years without anyone noticing.
The rule: only rain down the outside drain.
The page on how your home connects to the river explained the two-pipe system: foul sewer to the treatment works, surface water drain to the river. This page is about making sure your own pipes obey it.
A misconnection is a plumbing error that joins a wastewater pipe to the surface water system, so that a sink, appliance or even a toilet discharges, untreated, into a local stream or river every time it is used 13. Misconnections are usually innocent, often dating from an extension, a new bathroom or a moved kitchen, and the householder rarely knows. They are also common: Defra figures suggest up to 500,000 UK homes could be misconnected 14. On a catchment like the Dart, where Friends of the Dart's testing has found several small tributaries carrying consistently high bacteria levels 12, misconnections are exactly the kind of quiet, chronic source that keeps a stream dirty in dry weather.
Check what should be connected where. Your toilet, bath, shower, all sinks, washing machine and dishwasher should drain to the foul sewer; only rainwater from roofs, drives and paths should enter the surface water drain 17.
Do a simple home check. On a dry day, lift the obvious clues into view. Does a washing machine or sink waste pipe run into an outside gully that also takes a downpipe? Does a gully smell of washing water or drains rather than nothing? Run a tap or the machine and watch which grating the water appears in. If anything looks doubtful, ConnectRight, the national partnership on misconnections, advises contacting your water company, your local authority or a WaterSafe-approved plumber to investigate and put it right 13. Why it helps the Dart: correcting one misconnection stops a permanent, daily dribble of dirty water into a stream. How hard: the check is easy; a repair is a moderate plumbing job, and it is the owner's responsibility to fix.
If you extend or re-plumb, say the words "foul sewer" out loud. When builders or plumbers add a bathroom, utility room or kitchen, ask them to confirm the new wastewater connections go to the foul sewer, not the nearest convenient drain 13. Why it helps the Dart: it is far cheaper to connect correctly than to trace and fix later. How hard: easy, it is one question.
Join or run a Yellow Fish event. The Yellow Fish scheme, run under the national Catchment Based Approach partnership, stencils a yellow fish symbol beside surface water drains with the message "only rain down the drain", and comes with a toolkit for community groups 15. Why it helps the Dart: the fish makes the invisible pipe visible for every passer-by. How hard: easy, and sociable; see your community & the Dart.