Dr. Tom Ryan:

I certainly did not want to give the impression that single dwellings and their septic tanks are the sole pressure on our water quality. Water quality is a complex area and many pressures bear on quality. I thought it was important to set out the overall context. There is a decline there. Septic tanks are part of the pressure. We have a river basin management plan which states that domestic wastewater, including septic tank systems associated with one-off housing and unlicensed private urban wastewater treatment plants for small conurbations, is a substantial pressure on approximately 11% of water bodies which are identified as being at risk in the management plan. It is not an insignificant pressure and we have to manage it.