---
url: https://www.eurocovers.eu/glossary/biofilm
term: Biofilm
definition: A community of microorganisms adhered to a surface within an aquatic system, typically encased in a self-produced extracellular polymeric matrix.
updated: 2026-05-25
---

# Biofilm

A community of microorganisms adhered to a surface within an aquatic system, typically encased in a self-produced extracellular polymeric matrix.

A **biofilm** is a community of microorganisms adhered to a surface within an aquatic system. In
water utility distribution systems, biofilm drives operational and water-quality issues including
chlorine demand, taste-and-odor complaints, and corrosion. Reducing algae load at the source —
via floating covers on storage reservoirs — reduces the precursors that feed downstream biofilm
formation.