05. Mill Zelden van Passe - Zoeterwoude

The ‘Zelden van Passe’. If you cycle along the exit of the A4 on the N206, you can see in the distance the windmill of the Groote Westeindsche polder. This is the ‘Zelden van Passe’ which was built between 1645 and 1646. The name probably originated because, as a miller, it was difficult to please everyone (or ‘seldom convenient’). The water had to be kept as low as possible, but not too low so that farmers could still sail through the ditches with their barges (a simple open cargo vessel).

The mill is also the oldest still existing signal mill in Rijnland. Polders south of the Rijn and along the Gouwe were bound to a pumping level (a determined water level) until 1974. When the water in the rivers became too high, the polders were no longer allowed to discharge water. This was to prevent flooding.

To indicate that this pumping level had been reached, some mills were designated as signal mills. Later this task was taken over by pumping stations. When the miller of this mill gave the signal, which during the day consisted of hoisting a flag and in the evening lighting a lantern, the surrounding millers had to immediately stop draining. Although the Zelden van Passe was replaced by a pumping station in 1959, it continued to function as a signal mill until 1974.