This paper presents an attempt to synthesize deposition and ecosystem transport of sulphur and chloride through a strongly acidified lake watershed on the Swedish west coast. The results are based on field monitoring during a two-year period of concentrations in air, precipitation, streams and lakes. The water transport was monitored in three small watersheds and at the outlet of the total watershed. The dry deposition was estimated from concentration measurements and deposition velocities. Besides, throughfall was monitored in one small forested watershed. The estimated depositions into different subsystems were in good agreement with monitored outflows. The sulphur deposition to areas with coniferous forests were estimated to be 25-31 kg/ha·yr and to lake areas to about 19 kg/ha·yr. The marine part of the input is about 10%. The estimated retention of sulphur in the total watershed is 8-21%.