Drinking Water Quality

Note that there are currently no exceedences in drinking water supply and Limerick City Council is not on the Remedial Action List.

 

At our Water Treatment Facility in Clareville, the drinking water undergoes a treatment and testing process before being pumped to the storage reservoirs at Newcastle. From these reservoirs, it gravitates through a series of strategic trunk mains to Limerick City and into the distribution network of pipes and onto the consumer tap.

Drinking bottled water has become very popular but the water from the tap has to undergo far more stringent tests than bottled water. Tap water supplied by Limerick City Council consistently passes the water standards set by the European Drinking Water Directive of 1998 and must be in compliance with the European Communities (Drinking water) (No 2) Regulations 2007 (S.I 278 of 2007).

Limerick City Council Laboratory staff complete over 25,000 tests per year to look for over fifty different substances. Independent checking of drinking water quality is carried out by the Health Service Executive and the Environmental Protection Agency.

Details of the Water quality results received are attached below.

   Current Drinking Water Audit Monitoring Results (Excel - 84 Kb)
    EPA Drinking Water Audit Monitoring up to 31st July 2013

   Current Drinking Water Quality Results (Excel - 226 Kb)
    Results for City Drinking Water 1st Jan 2010 to 31st July 2013

   Cryptosporidium Monitoring Results (Excel - 98 Kb)
    Results for period 1st Jan 2010 - 31st July 2013

   Lead Monitoring Results (Excel - 45 Kb)
    Lead Results for City 1st Jan - 31st July 2013

   Location of Lead Pipe Connections (EPS - 101 Kb)
    This document lists the locations of lead pipes used throughout Limerick City.

Water Sampling Locations

This map shows the water sampling locations used by Limerick City Council.

Water Sampling Locations
EPS - 347 kbs

Information on Water Analysis

Chlorine

Chlorine is used to destroy disease-causing organisms in water, an essential step in delivering safe drinking water and protecting public health. Chlorine is by far the most commonly used disinfectant in all regions of the world. Where widely adopted, chlorine has helped to virtually eliminate waterborne diseases such as cholera, typhoid and dysentery. Chlorine also eliminates slime bacteria, molds and algae that commonly grow in water supply reservoirs, on the walls of water mains and in storage tanks. Only chlorine-based disinfectants leave a beneficial “residual” level that remains in treated water, helping to protect it during distribution and storage. The chlorine residual or Free Chlorine present in the distribution system is normally > 0.1 mg/l

E.Coli (Escherichia Coli)

The most important indicators of drinking water quality in Ireland are the microbiological parameters and, in particular, E. coli. E. coli 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 treatment plant is not operating adequately. E. coli is not itself a harmful organism but indicates that harmful organisms may be present. The drinking water regulations require a maximum limit of zero (0) E. coli per 100 ml in a water supply (after treatment).

Lead (Pb)

Lead is present in drinking water primarily from its dissolution from lead pipes or lead-containing solder and thus the concentration of lead in drinking water depends on a number of factors including pH, temperature, water hardness and standing time of the water. Consequently, the method of sampling for lead is critical and depending on the method used results can vary significantly. According to the World Health Organisation (WHO, 2004) lead is a general toxicant that accumulates in bone. Infants, children up to 6 years of age and pregnant women are the most susceptible to its health effects. It is toxic to both the central and peripheral nervous systems. The drinking water regulations require a maximum limit of 25 ug/l in a water supply up to the 24th of December 2013 and 10 ug/l in water supply thereafter.

Nitrate (NO3)

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). The nitrate converts to nitrite which reacts with blood haemoglobin thus reducing the availability of the blood to hold oxygen. The drinking water regulations require a maximum limit of 50 mg/l in a water supply.

Trihalomethanes (THM)

THM compounds are undesirable in drinking water for two reasons. Firstly, the actual compounds themselves may pose a hazard to the health of the consumer if present in excessive amounts, as chloroform is a suspected carcinogen. Secondly, the presence of the THM group may be an indicator of the possible presence of other organic by-products of chlorination in trace amounts. The WHO advises that ''In controlling trihalomethanes, a multistep treatment system should be used to reduce organic trihalomethane precursors, and primary consideration should be given to ensuring that disinfection is never compromised''. The drinking water regulations require a maximum limit of 100 ug/l in a water supply.

Aluminium (Al)

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 relationship 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 causal 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'.

The drinking water regulations require a maximum limit of 200 ug/l in a water supply.

Turbidity (NTU)

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 oocysts. While the parametric value for turbidity (at the tap) is that the water must be ''acceptable to consumers and [there must be] no abnormal change'' there is a parametric value for turbidity (for water leaving the treatment plant) of 1.0 NTU. However, it must be stressed that this value is for visual acceptability of the water. In practice turbidity levels need to be much lower and should not exceed 0.2 NTU and preferably be below 0.1 NTU to be protective against Cryptosporidium breakthrough in the treatment plant.

The drinking water regulations require a maximum limit of 1 NTU in a water supply.

Fluoride

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.

The drinking water regulations require a limit of between 0.6 mg/l and 0.8mg/l in a water supply.


Cryptosporidium

There is no regulatory requirement for the Water services Authority to monitor for Cryptosporidium. However, Limerick City Council, monitor for this organism on a weekly basis at it’s production facility in Clareville and monthly in its distribution system

Cryptosporidiosis is typically an acute short-term infection but can become severe and non-resolving in children and immunocompromised individuals. In humans, it remains in the lower intestine and may remain for up to five weeks. The parasite is transmitted by environmentally hardy cysts (oocysts) that, once ingested, excyst in the small intestine and result in an infection of intestinal epithelial tissue.

The drinking water regulations require a maximum limit of < 1 Oocyst per 10 litres in a water supply (after treatment).

 

Last update:15/08/2013

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