Guide

Preventing water pollution

Causes of water pollution

Water pollution has damaging effects on the environment, humans, plants and animals. Pollution can occur if your business discharges substances into surface waters or groundwater without prior treatment or by accident, eg after a spill.

The most common causes of water pollution include:

  • spills or leaks from oil and chemical containers
  • trade effluent going into surface water drains instead of foul water drains, or straight into watercourses
  • removing too much water from surface waters and groundwater
  • run-off containing fertilisers and pesticides from farming into surface waters
  • run-off containing salt during winter months
  • silt and soil from construction sites and bank erosion on farms
  • wash waters and waste products
  • fuel spills
  • releases of hot water
  • spills of food products, eg dairy products and fruit juice

If you pollute the water environment, you may be committing an offence.

Surface waters and groundwater are protected by a number of licensing regimes that prevent and control water pollution from businesses.

Point source and diffuse water pollution

Point source water pollution occurs where pollution comes from a specific, identifiable source, such as a sewage pipe or factory wastewater pipe.

Diffuse water pollution is caused by various sources, which are often hard to identify. Individual sources may be relatively small, but the combined effect of numerous sources can be damaging. Diffuse pollution has a greater impact on the water environment than any other source of pollution.

In rural areas, sources of diffuse water pollution include:

  • run-off from agricultural land containing substances including pest control products, animal medicines, slurry, sewage sludge and manure
  • run-off and leaching from contaminated land
  • silt and dust from mining, quarrying, construction and demolition
  • groundwater drainage discharging from disused mines
  • incorrect waste pipe connections

In urban areas, sources of diffuse water pollution include:

  • pollutants from car parks and transport, such as oil and brake fluid, rubber and metal from tyres and brakes, exhaust emissions, and detergents and grease from vehicle cleaning
  • heavy metals and pollution washed from roofs
  • animal faeces, for example from dogs and birds

You can prevent diffuse water pollution by: