In America, septic tanks are the most frequently reported sources of groundwater contamination. Parasites (including protozoans and worms), viruses and bacteria are wastewater pathogens that pose health risks to humans. Fungi that can cause respiratory, eye and skin infections also breed in sewage sludge. These viruses and bacteria are transported very quickly and contaminate drinking water supplies, as well as recreational surface waters.
Bacteria are miniscule organisms that are associated with several wastewater-related health issues, including cholera, gastroenteritis, bacillary dysentery, paratyphoid and typhoid. Most infect the intestinal tract and stomach, causing symptoms such as diarrhea (often bloody), headache, vomiting, nausea, fever and abdominal cramps. Depending on the type of bacteria, symptoms can manifest in hours or days after ingestion.
A virus cannot multiply outside of a host, and even though wastewater is a hostile environment for viruses, enough of them can survive in water to make humans sick. Viral gastroenteritis, polio and hepatitis A are a few diseases which can be contracted from malfunctioning septic tanks. In fact, there may be as many as 100 different viruses in raw sewage, but they are not easy to identify. HIV, however, cannot be transmitted through contact with wastewater.
The best strategy for preventing potential hazards from polluting water is to have a septic contractor regularly inspect, clean and maintain your system.