Backflow is a term in plumbing for an unwanted flow of water in the reverse direction.[1] It can be a serious health risk for the contamination of potable water supplies with foul water. In the most obvious case, a toilet flush cistern and its water supply must be isolated from the toilet bowl. For this reason, building codes mandate a series of measures and backflow prevention devices to prevent backflow.
- ^ Treloar, R.D. (2006). "Backflow Prevention". Plumbing (3rd ed.). Blackwell. p. 86. ISBN 978-1-4051-3962-5.