The grandest of all is at Marais à la Coque in Grouville. Owned by the parish, it stands on what was previously Crown land at the junction of Rue du Marais à la Coque and Rue Malo. The lavoir has a hand-operated pump which supplies a granite trough, and a large washing area. Alongside is a more modern pump on a granite platform 1.5 metres high, which is reached by steps on either side.
The name is frequently misspelled "cocque". The derivation of the name coque in this context is uncertain. The word means either 'shell' (oeufs à la coque are eggs in their shells) or a small loop or bow of ribbon used in making hats: marais is French for marsh.
