The health effects of drinking contaminated water can range from no physical impact to severe illness or even death. Some of the effects of drinking contaminated water can be immediate, or not noticed for many years. These include gastrointestinal and stomach illnesses like: nausea. The health effects of drinking contaminated water can range from no physical impact to severe illness or even death. Some of the effects of drinking contaminated water can be immediate, or not noticed for many years. These include gastrointestinal and stomach illnesses like: nausea. The health effects of drinking contaminated water can range from no physical impact to severe illness or even death. Some of the effects of drinking contaminated water can be immediate, or not noticed for many years. These include gastrointestinal and stomach illnesses like: nausea. The health effects of drinking contaminated water can range from no physical impact to severe illness or even death. Some of the effects of drinking contaminated water can be immediate, or not noticed for many years. These include gastrointestinal and stomach illnesses like: nausea.