At least part of the responsibility for these contaminated groundwater samples must lie with poor wastewater treatment or disposal facilities. And while city dwellers can shake their heads at the notion that 21st century Ireland might have an issue with wastewater, the reality is that in many rural areas, a septic tank has been the only means of dealing with household waste. The Environmental Protection Agency published its Waste Water Treatment Manual for Single House Treatment Systems, which was designed to achieve satisfactory practice in the design, construction and maintenance of septic tank drainage systems. But despite their widespread use, DETA (the Domestic Effluent Treatment Association) has stated that the industry needs a rethink regarding what it sees (a) as the preferential treatment afforded by the EPA to septic tank systems, and (b) into standards governing the waste water treatment sector.

Still, it would outline the differences between a conventional septic tank and a waste water treatment system.

According to DETA, a conventional septic tank processes wastewater by anaerobic activity and solids settlement only, and is totally dependant on the soil /disposal system to treat the wastewater prior to entry to the ground water.

On the other hand, a sewage treatment system incorporates options for both anaerobic/aerobic processes ensuring that the treated wastewater is a very high standard. The wastewater is treated to such a degree that it can be disposed safely into the soil and the ground water.

There have, of course, been some concerns regarding the suitability of such systems for all sites, as well as concerns with leakages and smells that can come with wastewater systems, but DETA dismisses these concerns, saying that wastewater treatment systems can work on almost all sites, whereas a septic tank will not work in certain soil conditions. And regarding the smell's and leakages, these are mostly down to poor design and installation.

"Wastewater treatment systems that are properly designed, certified by the Irish Agreement Board and conforming to the European directive EN12566 and installed correctly do not smell or leak contaminants, " said the DETA statement.

Of course, any treatment system, whether septic tank or wastewater treatment system, needs to be maintained, and de-sludging is an important element of a septic tank system, which should be done every three to five years or so.

The decision regarding what sort of system to elect for is really down to the individual, although certain things should be borne in mind. A septic tank is a cheaper option, although it may not be suitable for some sites. A wastewater treatment system does not depend on soil quality and does allow for disinfection and nutrient removal. But it may be more expensive, both to install and to run.

Still, as with almost any system in any business in any sector, the effectiveness of a treatment system, whether septic tank or wastewater treatment system, depends on the quality of the product and the quality of installation. And, according to Frank Cavanagh of bioCycle Ltd (an award winning wastewater treatment system which combines aerobic and anaerobic treatments), the current standards are not only inadequate, but also deceptive.

"One glaring lacuna in the construction industry is the area of wastewater treatment and disposal, with its potentially serious implications for property values, environmental pollution, public health and claims for damages when developments are constructed in unsewered areas, " he said. "Each year tens of thousands of septic tanks and assorted treatment systems are being installed throughout the country with blanket official approval, many of which will cause pollution and risk to public health simply because the present official policy provides for designers, suppliers, installers etc. to evade responsibility and for homeowners alone, who may have no particular knowledge of the subject, to be totally liable."

According to Cavanagh (and seconded by the unfortunate population which is affected by such problems), the more common issues associated with unsuitable or ineffective treatment and disposal systems are obnoxious odours, ponding of effluent, pollution of ground, surface or drinking water, mosquito or other insect infestation, frequent costly pump outs, suppliers gone out of business etc, again leaving the homeowner with an intractable problem.

"Amazingly, instead of compelling suppliers, designers, installers of septic tanks and wastewater treatment systems to comply with best engineering practice and to meet a specific level of effluent quality prior to discharge to the environment, the Department of Environment has legalised a faulty certification system which has facilitated deception, fraud and malpractice in the wastewater treatment industry and initiated a race to the bottom with corporate profits taking precedence over a duty of care to the consumer and environmental responsibility, " he said.

"This official certification of small and ineffective treatment systems is responsible for deceiving planning officials, consumers, and the construction industry into believing that all treatment systems are superior to septic tank systems and may be used in sites found to be unsuitable for septic tanks, " he continued. "In fact, the lack of appropriate design, inadequate capacity, and absence of essential safety features will render these systems more detrimental to the environment in the event of system malfunction than septic tanks."

So be warned, and perhaps go the extra mile in terms of assessing the viability of your system before it becomes an issue.