The New Dutch Waterline has been mobilised three times:
- at the outbreak of the Franco-Prussian War (1870),
- during the First World War (1914-1918) and
- at the beginning of the Second World War.
The New Dutch Waterline was permanently manned by around 12,000 troops. During periods of international tension, 6000 troops were added. When war was imminent, the Line was brought up to its full strength, meaning 33,000 tot 36,000 troops were encamped there.
The mobilisation of 1870 brought several shortcomings to light. There were too few bombproof shelters. The weaponry was hopelessly out of date. And the fortifications were in poor shape. In 1874, the Minister of War announced the Fortification Act as a way to improve the New Dutch Waterline as a whole.
During wartime, life for residents around a fort also changed. Before World War II, the town of Asperen had around 1300 residents. The arrival of hundreds of soldiers must have seemed like an invasion. Still, there were few problems. Some of the neighbouring residents were even happy with the arriving soldiers as they brought income to the region.