A semiquantitative approach of the hydrogeological regime of the Adra (Honda and Nueva) lagoons has been done, based on periodical monitoring of a number of hydrological variables along 1999 and 2000, then tested with a monthly water balance. The Adra deltaic aquifer, over which the lagoons are situated, shows piezometricpiezometric variations during the last 25 years due to changes in recharge (beginning of the operation of a reservoir upstream in 1982). At present, the Honda lagoon is mainly recharged by water coming from irrigation channels and from sporadic runoff (oueds). As regards to the aquifer, it behaves as a predominantly losing lake, specially during high-level periods. A major fraction of its groundwater discharge flows towards the adjacent -and nearer to the shore- lagoon (Nueva), and from here, in certain periods, towards the sea. Thus acting as a flow-through lake. The Nueva lagoon has a general behaviour as a gaining lake, although at present incoming water from irrigation channels is also significant.