The answer is yes. Most of the houses that do not have access to a local authority sewer rely on a septic tank or a sewage treatment plant for drainage and will require a percolation area.
In its simplest form, a septic tank is a tank which removes the gross solids from the sewage by settlement. The effluent leaving the septic tank still contains many of the contaminants of raw sewage and requires further treatment before its disposal can be regarded as satisfactory. For single houses in Ireland the most appropriate effluent treatment is regarded as percolation through a medium, usually soil.
During the passage of effluent through the medium, processes take place which reduce the number of soluble and microbiological contaminants. Where soil and ground water conditions are suitable, this treatment gives satisfactory results. Where conditions are not suitable then local nuisance or water pollution can occur.
The result is the ponding of effluent which give smells and surface water pollution. The old-fashioned way of dealing with this effluent was to have it discharged from the septic tank into a pit filled with stones from which the effluent was dispersed by soakage or percolation. This was called a soak pit.
The modern practice is to lay distribution pipes into which the effluent can flow and be gradually dispersed into the soil over a larger area. This area is called a percolation area. The pipes are loose jointed so that the dispersal of effluent through the earth takes place over as broad an area as possible.
All sorts of factors affect the smooth operation of septic tank and percolation area drainage systems such as proximity to a river, height of the water table, the permeability of the soil etc. If doubts arise as to whether the drainage system is adequate, the most important matter you should consider and get your surveyor to advise on is whether a new septic tank and percolation area could be installed within the confines of the site, and of course approximately what this would cost.
At least you will then know that if problems develop you should be able to sort them out, even if that is at a price.
In recent years more modern treatment plants are almost universally used for treatment of wastewater from houses but the basic principles are similar in that they comprise a tank and require a percolation area to disperse the effluent. You should also ask your surveyor to let you know if the septic tank or any part of the percolation area is the required distance from the house, roadway and boundary as laid down in the EPA Code of Practice, or is outside the site, and pass on this information to your instructed solicitor.