This article gives an overview of risks and lessons learned about geomembrane constructions in The Netherlands and abroad. Subjects that will be discussed will include risk-assessments and quantification of risks regarding geomembranes, welding procedures, stability issues of slopes, backfill and retaining structures, installation damage by handling and weather circumstances, and external influences after completion. The aim of this paper is to emphasize an integral approach during the entire process and importance of acknowledging quality risks to all involved companies. The success of a watertight and durable installation will depend on an integration of design aspects, materials, construction issues and quality assurance. To avoid risks during lifetime attention shall be given to proper restrictions, maintenance issues and monitoring of leakage/durability. The article presents examples, to illustrate risks and lessons learned. This article is supporting a specialty session at the Eurogeo6 congress Slovenia (Slovenia) in September 2016. A full colour summarized version of this article is published in a Congress Magazine by Educom publishers.