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C6.1 Regulations for water quality


Regulatory instruments for controlling water quality can be aimed at controlling discharges at source, or at managing the receiving environment. They also include regulations for waste minimisation.

Uniform emission or discharge standards apply to all emissions in a specific area (emission approach). Specific emission standards can be set in individual permits. These can be based on the pertinent ambient water quality standards (water quality approach) or on the best available technology (BAT), best practicable technology (BPT) or the best available technology not involving excessive costs (BATNEEC).

A combined approach implies that minimum uniform emission standards are set and that stricter standards are applied if the quality of the receiving water requires it, or if the way the water is used requires higher standards (e.g. for maintaining a delicate ecosystem). Specific regulatory instruments can also be used to protect aquatic ecosystems and riparian habitats, and for the rehabilitation of water resources.

Where discharge standards are difficult to apply, as in the case of non-point pollution, regulations may focus on the techniques or practices; in agriculture for example the best environmental practice approach, which will provide guidelines for the application of fertilisers and pesticides, is often used. Regulatory instruments can be developed for the protection of groundwater, taking into account the difficulties of monitoring and rehabilitating groundwater. Other types of regulatory instruments include:

  • Product standards, which can be set for some pollutants, such as pesticides, and the widespread banning of DDT;
  • Land use controls, which may influence the setting of ambient or discharge standards (C6.4);
  • Safety regulations and procedures for accidental pollution may also be useful.

The application of regulatory instruments for water quality control should be based on environmental goals that are set in the policy and planning stage (A1, B1.5, B2.3). Furthermore, administration and setting water quality standards must be closely linked with regulations for water quantity, as these are inter-dependent (C6.2).

Lessons learned

  • An ambient water quality approach is usually based on set priorities and is more complex to apply than an emission approach.
  • An ambient water quality approach requires the availability of rather detailed water quality data from the recipients (C1.1).
  • For regulations to be effective they need to be implemented by institutions with the capacity for implementation, compliance monitoring and enforcement (B2.3).
  • A water quality approach can lead to different regulatory conditions for similar polluters (and pollutants) in different basins because the condition of the receiving environment, which is used to determine the discharge or abstraction standards, is likely to differ in different locations. This may be politically harder to introduce than the application of uniform standards.
  • An emission approach or pollution control based on Best Available Technology is essential for pollutants that accumulate in the environment.
  • Product standards are appropriate for diffuse pollution because emissions are difficult to monitor.
  • Standards should be achievable in the short term, but they should also stimulate further improvements in the long term through progressive tightening.
  • Tools need to be balanced e.g. restricting infiltration may increase urban run-off.
  • In low income countries, definitions of what is safe need to be balanced with what is affordable and appropriate.

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