A drain on resources

STROLLING along the banks of London's rivers and streams, your back-to-nature experience is likely to be marred by the visible pollution contaminating the waterways.

A rainbow-hued swirl of oil, an unsightly scum on the surface, soggy rags and unspeakable nasties (and the contaminants that aren't seen by the naked eye are equally unpleasant). But before you reach for your mobile to call a crusading Erin Brockovich to bring careless corporations to justice, check first whether the culprit lives nearer to home.

"Our estimates show that household waste from about one in 10 properties in London runs into the capital's streams and rivers," says Matt Prior, manager of Thames Water's Environmental Protection Team.

He adds that in some boroughs, such as Brent, Haringey and Barnet, the figure is closer to one in three. "Most people aren't aware of the issue, but incorrectly connected drains pose a huge environmental problem for the capital."

Bad connections occur when household appliances, such as washing machines or dishwashers, or fixtures such as toilets, sinks, showers and baths, are plumbed into the wrong pipe or manhole. More often than not, it will be a DIY plumbing job that has created the problem, but even qualified plumbers can make mistakes.

"There are two separate drainage systems in most areas," explains Prior.

"One for foul water, one for surface water. The foul-water sewer system takes all the waste water from a property to a sewage- treatment works, whereas the surface-water system collects rainwater from roof guttering, driveways, patios etc, and carries it, untreated, to the local river."

When a polluted waterway is reported, Prior's team works in conjunction with the Environment Agency to trace the source of contamination. Often the investigation starts as a result of a call from a concerned local resident.

"We get a lot of feedback from the general public about the polluted state of their local brooks and streams," says environment officer Sarah Hargreaves, describing in gruesome detail the types of pollution, and its impact.

"The effluent lowers the oxygen levels, suffocating all normal pond life and resulting in the growth of a grey sewage fungus on the bed of the stream. The visible impact is very unpleasant, too, especially for people who live near the waterways. They'll often see solids from toilets floating past and, in the summer, can't open their windows because of the horrible smell."

Thames Water and the Environment Agency work together to track down the incorrectly connected pipes in a particular catchment area, using pollution-tracing techniques such as wire baskets on junctions of surface-water sewers, coloured dyes and even remote cameras in the pipes.

"Usually, the homeowners are completely unaware that their pipes are incorrectly connected," she says.

One such homeowner was Mr Shah of Edgware, who was contacted by Thames Water when they suspected his property was causing a pollution problem. "I didn't realise anything was wrong with our pipes," he confesses. "We bought the house four years ago and the surveyor didn't pick up anything at that time."

Having traced the pollution to Shah's house, Thames Water ran dye through all the waste pipes to discover that the shower and washbasin in the bathroom were plumbed into the surface water drain, sending soapy waste water directly into the local brook.

Eco-conscious Shah, who composts his kitchen waste and uses four separate bins for recycling, was horrified to learn he was contributingto environmental pollution, and promptly rang for a plumber.

The work to rectify the problem he inherited will be at his own expense because, like all homeowners, he is legally responsible for his private drains up to the point where they connect to the public sewer, often beyond the boundary of the property itself.

Over the past 12 months, more than 700 incorrectly connected drains have been discovered, affecting 40 different rivers and streams, all of which have since been reconnected.

Thames Water points out that if homeowners carry out the necessary work to correct incorrectly connected drains, no legal action will be taken against them. Failure to rectify the problem can lead to a maximum fine of pounds 2,000 or, in the worst cases, the Environmental Health Department can serve notice and undertake the work at the owner's expense.

Clean up your act at home

THAMES Water produces a helpful leaflet for homeowners, advising on the type of household waste products that should be "bagged and binned".

Inconsiderate disposal of such items as cooking fat and kitchen waste (that are typically swilled down the sink) can cause blockages in the main waste water system.

This can result in flooding of roads and properties, and can cause contaminated water to overflow into surface-water sewers, which lead to rivers and streams. Bear in mind, too, that contaminants such as engine oil or garden chemicals that are poured into drains or gutters in the street will flow untreated into your local stream or river. Follow these tips to help keep your local rivers clean: . Items that should be put in a biodegradable bag, or wrapped in tissue prior to being put in the bin, include bandages and surgical dressings, condoms, cotton wool and cotton buds, incontinence pads, nappies and female hygiene products.

. Cooking fat should be allowed to cool and solidify before being transferred to the bin. Wipe up liquid oils with kitchen towel.

. Your local authority should be able to assist in the disposal of engine oil, concentrated household or garden chemicals, paint and solvents.

. Drugs and medicines should be returned to your local pharmacy, and your local health authority or surgery will assist in disposing of syringes.

To order the Bag it and Bin it leaflet, call Thames Water on 0845 9200 800.

Troubleshooting

IT IS relatively simple to check if your drains are not connected properly.

Look at the soil stack on the outside of your home (the 4in-wide waste pipe leading from the toilet): . Do all your other waste pipes exiting the house connect to this soil stack? If so, you are correctly connected.

. Do any waste pipes from your house lead into the rainwater drainpipe that runs from your roof?

If so, you have a badly connected system.

. Do any waste pipes from your house run directly to a grating at the foot of the property? If so, you have a badly connected system.

If you do find a bad connection, make sure you use a qualified plumber to put it right. Remember, even if you didn't cause the problem, you could be liable for prosecution. The work will be at your own cost unless the wrong connection was approved by a local authority Building Control department. The council's responsibility is deemed to last for 14 years. To report pollution, call the Environment Agency emergency hotline on 0800 807 060.

Copyright 2003
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