The Operation Streamclean team traces sources of watercourse pollution using CCTV technology, dye testing, and sampling equipment.
Previous surveys of more than 3,000 properties close to Brislington Brook found that 173 washing machines, 92 dishwashers, 157 kitchen sinks, 116 washing basins, 53 baths, 52 showers, and 66 toilets were wrongly connected.
A total of 255 properties were found to have been misconnected and residents have made the changes after being informed by Wessex Water.
These were hooked up to the surface water drainage system, designed to collect rainwater and discharge it into local streams, rather than the foul sewer system.
Wessex Water Streamclean co-ordinator Larry Spiers said: “Problems occur when household appliances, such as washing machines, have been misconnected to the surface water system, which leads to foul water being discharged into streams without being treated.
“This damages the environment and could be a potential health hazard.”
The work coincides with Bristol’s year as the European Green Capital and Bristol 2015 chairman Andrew Garrad said: “It is initiatives such as this one that really help to improve the local environment.”
In March this year, Thames Water stated it is hunting for up to 60,000 misconnections, with an estimated 10 per cent households suffering from plumbing errors.