Water and Drainage
Drinking Water Quality
Drinking water samples are taken regularly throughout the water distribution network and tested for a wide range of parameters in accordance with EU Regulations. Testing is carried out at Dublin City Council's Central Laboratory which is independently accredited by the National Accreditation Board to undertake and certify these tests. Water supplied in this county routinely achieves a compliance in excess of 99% and is among the highest quality in the country.
Where an exceedence of a parametric limit occurs, the Water Department is required to submit immediate notification to the Environmental Protection Agency (EPA) giving details of the exceedence and of remedial measures proposed. If there is a potential danger to human health, the HSE is consulted on actions, advice and notifications to be undertaken. This may take the form of detailed information and locations on the Council's Emergency Updates Blog (see www.dlremergencyupdates.blogspot.ie ) and/or measures such as direct letter drop to affected consumers.
Descriptions of Sampling Locations
In compliance with EU Drinking Water Regulations, water samples for testing are taken at treatment works and at various locations throughout the distribution network including at the actual point of use i.e. consumer taps. Sample locations are chosen to be representative of water quality throughout the network and include private premises, public buildings and commercial premises.
Test Results of Main Parameters
Monthly results of compliance for the main parameters for each water service area can be accessed through the links below. The number of Parametric Value Exceedances are tabulated by supply and parameter. The table below explains the abbreviations used in the result tables, the significance of each parameter and the EU limits.
| Abbreviation | Details |
|---|---|
| Col |
Parameter : Colour |
| Odour | Parameter : Odour Limit : Acceptable to consumers and no abnormal change |
| Taste | Parameter : Taste Limit : Acceptable to consumers and no abnormal change |
| Cond | Parameter : Conductivity Limit : 2500 μS cm -1 at 20 OC Conductivity is a measure of the ability of water to conduct an electrical current, therefore conductivity is related to the ionic content of the water. The water should not be aggressive. |
| TC | Parameter : Coliform Bacteria Limit : 0 No./100ml The coliform bacteria (previously known as Total Coliforms) are a group of organisms that can survive and grow in water. They are a useful indicator of treatment efficiency and the cleanliness of the distribution mains. Coliform bacteria can occur in sewage and in natural waters. Coliform bacteria should not be present in water that is disinfected and their presence indicates that either disinfection has not been complete, that there is ingress into the watermains in the distribution network or that the sample point is contaminated. |
| Ec | Parameter : Escherichia Coli (E.Coli) Limit : 0 No./100ml The E.Coli bacteria is present in very high numbers in human or animal faeces and is rarely found in the absence of faecal pollution. As such, its presence in drinking water is a good indication that either the source of the water has become contaminated or that the treatment process at the water treatment plant is not operating adequately. |
| C. Perf | Parameter : Clostridium Perfringens (incl. spores) Limit : 0 No./100ml Clostridium perfringens is a member of the bacterial intestinal flora of humans and therefore serves as an indicator of faecal pollution. The spores of Clostridium perfringens are particularly resistant to unfavourable conditions in the environment and thus they survive for long periods. As such, they can be useful indicators of water that is intermittently polluted. |
| F | Parameter : Fluoride Limit : 0.8 mg/l in fluoridated supplies 1.5mg/l in naturally fluoridated supplies Fluoride arises almost exclusively from fluoridation of public water supplies and from industrial discharges, although it occurs naturally in quite rare instances. Past health studies have shown that the addition of fluoride to water supplies at levels above 0.6mg/l F- leads to a reduction in tooth decay in growing children and that the optimum beneficial effects were thought to occur around 1.0 mg/l. However, in light of recent international and Irish research which shows an increasing occurrence of dental fluorosis, the Forum on Fluoridation (2002) recommended the lowering of the fluoride levels in drinking water to a range of 0.6 to 0.8 mg/l, with a target of 0.7 mg/l. Local Authorities are legally obliged to fluoridate public water supplies. |
| Turb | Parameter : Turbidity Limit : Acceptable to consumers and no abnormal change The control of turbidity is one of the indicators of the efficiency of treatment at the plant. Elevated levels of turbidity in the treated water indicate that the treatment process is not operating adequately. It also provides a good indication of whether the treatment plant is capable of removing Cryptosporidium ocysts. |
| pH | Parameter : ph - Hydrogen Ion Concentration Limit : 6.5 to 9.5 pH units Hydrogen ion concentration (pH) is a measure of whether a liquid is acid or alkaline. The pH scale ranges from 0 (very acid) to 14 (very alkaline). the range of natural pH in fresh waters extends from around 4.5 for acid peaty upland waters to over 10 in waters where there is intense photosynthetic activity by algae. However, the most frequently encountered range is 6.5 to 8.0. the control of pH is a critical component of water treatment and distribution, influencing the effectiveness of coagulation, disinfection and the concentration of plumbing materials (such as lead, copper and nickel) in the final product. The water should not be aggressive. |
| NO3 | Parameter : Nitrate Limit : 50 mg/l Nitrate in the environment originates mostly from organic and inorganic sources such as waste discharges, animal slurries and artificial fertiliser. High levels of nitrate in drinking water may induce "blue baby" syndrome (methaemaglobinemia). |
| NO2 | Parameter : Nitrite Limit : 0.5 mg/l Nitrites exist in very low levels principally because the nitrogen will tend to exist in other forms (such as ammonia). Nitrite is an intermediate in the oxidation of ammonia to nitrate. Nitrite is associated with methaemaglobinemia. |
| NH4 | Parameter : Ammonium Limit : 0.3 mg/l Ammonium in water supplies originates from agricultural and industrial processes, as well as from disinfection with chloramines (a method of disinfection not in use in Ireland). Elevated levels of ammonium may arise from intensives agriculture in the catchment of the water sources. Ammonium is therefore an indicator of possible bacterial, sewage and animal waste pollution. Ammonium in itself is not a health risk but the parametric value serves as a valuable indicator of source pollution. |
| Al | Parameter : Aluminium Limit : 200 μg/l Aluminium is present in drinking water as a result of its use as aluminium sulphate (a coagulant) in the water treatment process, though can be naturally present in some waters. Historically, there has been some concern about possible links between aluminium in drinking water and Alzheimer's Disease. However, the WHO states that:- "On the whole, the positive relationships between aluminium in drinking water and Alzheimer's Disease which was demonstrated in several epidemiological studies, cannot be totally discounted. However, strong reservations about inferring a casual relationship are warranted in view of the failure of these studies to account for demonstrated confounding factors and for the total aluminium intake from all sources". |
| Fe | Parameter : Iron Limit : 200 μg/l Iron is an abundant metal found in the Earth's crust. It is naturally present in water but can also be present in drinking water from the use of iron coagulants or the corrosion of steel and cast iron pipes during water distribution. Iron is an essential element in human nutrition. The WHO (WHO, 2004) states that values of up to 2 mg/l (10 times the parametric value) do not present a hazard to health. However, at levels less than 2 mg/l but above the parametric value, the colour of water may turn brown, become turbid or may deposit solids on clothes washed in the water or food cooked using water. |
Monthly results of compliance for the main parameters for each water service area are posted below.
- 2012 Drinking Water Results (pdf -71kb)
- 2011 Drinking Water Results (pdf -68kb)
- 2010 Drinking Water Results (pdf -78kb)
- 2009 Drinking Water Results (pdf -90kb)
- 2008 Drinking Water Results (pdf -90kb)
See DLRCC Summary - Quality of Drinking Water in Ireland - 2010 (pdf -62kb) for a summary of the latest EPA report on quality of water in the County.
The full report may be read on the EPA Website or click here Provision & Quality of Drinking Water - 2010 - Full Report (pdf -3,788kb)
SUPPLY AREAS AND SOURCES
Sources listed below are the normal sources for each area. However, from time to time it is necessary to alter supplies for operational reasons.
| Zone | Source | Area Covered |
|---|---|---|
| 1 | Stillorgan Reservoir (primarily Ballymore Eustace and Roundwood Water) |
Blackrock, Booterstown, Clonkeen, Deansgrange, Dun Laoghaire Town (West of Marine Road), Foster's Avenue, Roebuck, Johnstown, Monkstown, Oatlands, Orpen, Pottery Road, Stradbrook |
| 2 | Ballyboden (Bohernabreena & Ballymore Eustace Water) |
Balally, Braemor, Central Park, Goatstown, Kellystown, Kingston, Lakelands, Mount Merrion (South), Nutgrove, Orwell, Pine Valley, Sandyford Industrial Estate, South Avenue |
| 3 | Ballyedmonduff (Local Supply) |
|
| 4 | Glencullen (Local Supply) | |
| 5 | Kilternan (Local Supply) | Glenamuck, Ballychorus |
| 6 |
Roundwood Reservoir |
Ardagh, Ballyman, Cabinteely, Cherrywood, Foxrock, Leopardstown, Merville, Mullinastill, Old Conna, Ralahine, Shanganagh, Shankill, Stillorgan Village, Watsons, Woodbrook |
| 7 | Church Road (primarily Ballymore Eustace & Roundwood Water via Stillorgan Reservoir) |
Ballinclea, Ballybrack, Dalkey, Dun Laoghaire Town (East of Marine Road), Glasthule, Glenageary, Killiney, Loughlinstown, Mounttown, Sallynoggin, Sandycove. |
| 8 | Saggart (BME) (Ballymore Eustace Water) |
Ballyogan, Broadford, Clonskeagh, Dundrum, Kilcross, Llewellyn, Marley Grange, Milltown, Sandyford, Stepaside, Sweetmount. |
