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In this section:


Advice for home owners in areas subject to Flooding


Domestic Wastewater Treatment Systems Registration (Septic Tank)

Domestic Wastewater Treatment Systems 2024

Surface Water Quality


Water Quality of Lakes


Effluent Discharge Licences


Water Quality and Agriculture/Nitrates Directive (GAP Regulations)


Guidelines for Slurry/Fertiliser Spreading



IMPORTANT NOTICE - Advice for home owners in areas subject to Flooding


The EPA has issued the following advice on Septic Tanks - what to do after flooding


  1. Due to the potential for toxic gases in all septic systems, any servicing, cleaning, repairs, internal damage assessments and emptying/ pumping must be carried out by trained and experienced specialists.
  2. After the flooding subsides, replace any dislodged manhole covers and check the system for any external signs of damage such as settlement, ponding of waste water, overflowing, blocked drains or not accepting water from the house.
  3. If you suspect damage, or if your system relies on electrical components such as pumps, have the entire system assessed by a professional service engineer.
  4. Ensure that any nearby private wells are checked and disinfected prior to use by following the EPA advice (available on for private well owners on what to do after flooding.,58775,en.html#.VoZLec8rHcs


As always, do not enter flood waters as manholes may have been dislodged and the flood water will be contaminated and may pose a risk to health.



Domestic Wastewater Treatment Systems Registration (Septic Tank)


Water Quality Legislation and Regulations


Statutory responsibility for water management and protection rests primarily with local authorities. Various pieces of legislation enable local authorities to:


  • prosecute for water pollution offences;
  • attach appropriate pollution control conditions in the licensing of effluent discharges from industry, etc., made to waters or to sewers;
  • issue notices ("section 12 notices") to members of the public or businesses, etc., specifying measures to be taken within a prescribed period to prevent water pollution.
  • issue notices requiring a person to cease the pollution of waters and requiring the mitigation or remedying of any effects of the pollution in the manner and within the period specified in such notices;
  • seek court orders, including High Court injunctions, to prevent, terminate, mitigate or remedy pollution/its effects;
  • prepare water quality management plans for any waters in or adjoining their functional areas;
  • make bye-laws regulating certain agricultural activities where the local authority considers this to be necessary so as to prevent or eliminate pollution of waters,
  • issue notices requiring farmers to prepare nutrient management plans with the aim of ensuring that nutrients applied to land from chemical fertilisers and organic farm wastes, e.g. slurries, take account of nutrients already available in the soil and are consistent with recommended application rates, crop requirement and the need to avoid water pollution.


Further information about water quality legislation and policy is available at and via the Enfo fact sheets.


The text of Irish Legislation can be viewed online in the Irish Statute Book available on the Attorney Generals website.


The Water Framework Directive 2000/60/EC is also a key legislation, which will focus work in the areas of Water Quality, through the establishment of River Basin Management Systems.



Surface Water Quality

The Environmental Protection Agency carries out monitoring of the biological river water quality at River Sites in County Donegal. Biological River Water quality is ranked by Q value, whereby the highest (best) Q rating is 5 and the lowest Q rating is 1. The EPA website contains interactive maps that give a map display of river monitoring stations colored by Q rating.

In addition, the EPA publishes a 3-year summary of its findings and looks at trends for rivers, lakes and estuarine waters. 


Water Quality of Lakes

With many lakes used as abstraction sources for drinking water, there is a comprehensive programme of monitoring carried out on lakes in the county. In addition, the EPA requires that of the 120 lakes, approximately 40 are monitored annually on a 3-year cycle, using the following 3 indicator parameters – total phosphorus, chlorophyll and water transparency, to assess the level of eutrophication and its’ effects. The input of phosphorus, primarily through losses from agricultural activities, (such as farmyard run-off & chemical fertilizer application), and municipal & industrial waste discharges, commonly results in algal, cyanobacterial and other plant growth, which in turn, leads to poor light penetration and oxygen depletion in the deeper layers of the lake.


The EPA reports on the water quality of lakes on a sliding scale from Oligotrophic, (unpolluted), mesotrophic, eutrophic to hypertrophic, (highly polluted).



Effluent Discharge Licences

Effluent discharges from commercial activities, including industries and hotels, may be classified into two types, each requiring a licence under different sections of the Local Government (Water Pollution) Act 1977 (as amended 1990). Discharges to waters are licenced under section 4 of the Act, and applications are made to the Local Authority. Discharges to sewers are licenced under section 16 of the Act and applications are to be made online to Irish Water.

The Council maintains a register of Section 4 licences issued. The application for a Section 4 Discharge Licence is similar to an application for Planning Permission, with the same necessity to publish a public notice in the press, and the same procedure for appeal (to An Bord Pleanala).  There is an ongoing programme of sampling discharges to ensure compliance with licence conditions and the Council may issue Notices (under section 12 of the Act), specifying measures to be taken within a prescribed period, to (a) prevent water pollution, and/or (b) cease the pollution of waters requiring mitigation or remedying of any effects of such pollution. The Council may also prosecute for water pollution offences, and/or seek court orders, including High Court Injunctions, to prevent, terminate, mitigate or remedy pollution and its effects.


 Application forms for discharge to waters are available here

 Guidelines for the Discharge of Effluent to Waters from Industrial Commercial De


Application forms for discharge to sewers are available here


Large industrial or agricultural activities require an Integrated Pollution Control Licence from the Environmental Protection Agency. Details of the classes of activities needing an IPC are available at


Further information can be obtained by contacting: Letterkenny PSC, Donegal County Council, Neil T Blaney Road, Letterkenny, Co. Donegal, F92 TNY3. Tel: 074 91 53900 



Water Quality and Agriculture/Nitrates Directive (GAP Regulations)

Loss of Phosphorus and Nitrogen from Agricultural Activities has been identified as a major contributing factor to the pollution of water bodies with these nutrients.

The EC GAP Regulations contain advice and recommendations for farmers as to -


  • farmyard management including storage of organic fertilisers
  • nutrient management
  • prevention of water pollution from fertilisers
  • certain activities
  • duties of occupiers
  • role of public authorities
  • soil testing
  • storage periods and closed periods for the application of fertilisers


Copies of this document are available from The Department of the Environment, and Donegal County Council Environment Section.



Guidelines for Slurry/Fertiliser Spreading


Check the weather forecast before spreading. Do not apply organic or chemical fertilisers when heavy rain is forecast within the next 48 hours.
Avoid spreading organic or chemical fertiliser:


  • on wet or waterlogged ground
  • on frozen or snow-covered land
  • on land sloping steeply towards rivers, streams, lakes and exposed bedrock


No Chemical Fertiliser should be applied within 1.5m of any watercourse.

Avoid polluting surface waters and wells by leaving a buffer strip between them and the land on which organic fertilisers are applied. The Table below sets out the general guidance on the widths that may be appropriate for buffer strips. It is essential that the recommended strip widths are observed in the case of domestic wells and public water supply sources. The width of the strip required to streams, lakes/drains and lake/main river channels will depend in each case on soil type, slop, and vegetative cover.


Recommended Buffer Strips (Meters)
Streams and Drains 10
Lakes and Main River Channels 20
Domestic Wells 50
Public Water Supply Sources 50-100


Further information on Agriculture in General can be obtained from the Department of Agriculture, Teagasc, IFA.


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