According to a recent scientific paper published in Science Daily from the University of East Anglia, the rates of illness caused in children by private drinking water are now equivalent to what you would expect in a developing country. 1% of the UK relies on a private spring, well or bore hole and 10% of children drinking from these supplies go down with around five bouts of sickness or diarrhea a year.
This sickness is not seen in adults, and so it might be that there are longer term health benefits, but the rates of associated hospitalisation of children are a concern. The study involved sampling the water supplies and testing for the presence of enteric bugs (bacteria normally associated with the gut, and therefore a marker of pollution). The study did not comment on whether or not this is something that is on the rise, but it might be as more pressure is placed on the environment.
The researchers studied more than 600 consumers in Norfolk, Suffolk and Herefordshire for 12 weeks. Those surveyed kept a diary of symptoms including diarrhea, vomiting, stomach pains, nausea, headache, and fever. Prof Paul Hunter, from UEA's Norwich Medical School, said: "We found a particularly high incidence of diarrhea in children under 10 in homes provided by water which was contaminated with bacteria. The results showed that these children would suffer almost five incidents a year -- a risk of illness similar to that reported in developing countries. It is very important that households reliant on private water supplies, where children under 10 live or visit, are identified and frequently tested for pollution. Our recommendation to parents is to either ensure adequate well-maintained treatment such as chlorination or filtration."