In 1399 Workum received city rights and with that the right of mint and measure. In the 15th century, a weigh house was built. The weighmaster supervised the correct weights and measures. The Waag was mainly used for trading butter and cheese.

In 1649, the weigh house was in very poor condition. The city council therefore decided to replace the it with a new building. A year later, a fine new weigh house was built in the center of the city on the Merk; the present building. The building has a hipped roof with a stepped gable dormer on each side. There are also coats of arms in the facades, including the municipal coat of arms with the year 1650.

In 1923, the Waag was restored. The lower floor served as a police station and the upper floor became a library and public reading room. After a new restoration in 2007, the building is used by the Tourist Information Centre and Museum Warkums Erfskip.