Why and how to prevent biofilm formation in drinking water pipes

A biofilm is a slimy layer sticking to the inside wall of the drinking water pipe that is created by the growth of microorganisms on mineral deposits or organic material. When the biofilm loosens or bacteria are released from it, problems such as reduced production, disease, decomposition / scavenging of water additives and a reduction in the effectiveness of medication can arise. Due to the presence of biofilm in the pipes, the bacterial pressure can rise incredibly between the water source and the drinking point! Moreover, biofilms can promote the development of antibiotic resistance. It’s important to focus on prevention of biofilm. Indeed, besides a poor bacteriological quality of the drinking water, biofilm can cause other problems such as blockage but also corrosion of the pipes. Furthermore, thick and tenacious biofilms will require high doses of strong biocides. This increases the risk of health problems due to biocide residues in the water. One hundred percent prevention is often not possible, but several measures can significantly slow down biofilm formation.

The piping material: polyethylene pipes are prone to biofilm formation whereas copper piping is less sensitive.

Bacteria love stagnant (warm) water: avoid dead ends in the piping and assure a good flow at all times.

Iron and manganese in the water promote biofilm formation. Check the DISARM best practice guide for water quality for methods to remove iron and manganese.

Regularly clean the pipes (see also DISARM best practice guide for water quality)

Some water treatments / additives (e.g., butyrate, acetic acid) can contribute significantly to the formation of biofilm or slime formation, depending on the water source.