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Domestic Waste water Treatment Systems

Domestic waste water treatment systems (DWWTS), mostly septic tanks, are used by householders to treat their sewage.

If properly designed, sited and installed, septic tank and other on site waste water treatment systems can do an excellent job of removing contaminants such as nutrients, organic matter and microbes from the waste water generated in our homes. This allows the treated water to be released back into the environment without causing either pollution of waters or health problems.

DWWTS pressures

If waste water is not properly treated it can cause nuisance, pollution or a risk to public health. The nutrients (phosphorus, ammonia, nitrate) and organic matter in domestic waste water are a particular problem for high status waters which tend to be very sensitive to even small increases in contaminants.  Issues with domestic waste water treatment systems can arise for a wide variety of reasons, for example:

  • the site conditions are sub optimal (too slow or too fast draining);
  • the site has not been properly assessed;
  • the system has not been properly designed;
  • the installation is not carried out to the correct standard;
  • the system is not maintained.

Pressures from domestic waste water treatment systems have increased in recent years so it is imperative that homeowners make sure that their treatment systems are working well.

The ‘Waters of LIFE’ project will work with communities in the pilot high-status objective catchment areas to implement measures where domestic waste water treatment systems are a significant pressure on rivers and lakes. Grants of up to €5,000 may be available to qualifying households to fix domestic waste water treatment systems found to be a risk to water bodies in high status objective areas. Details of the eligibility criteria and level of grants are available on the Department of Housing, Planning and Local Government website and from your local authority who administers the grants.

Further information regarding domestic waste water treatment systems can be found on the EPA’s website.