Las Tablas de Daimiel National Park (TDNP) is a Ramsar Mediterranean wetland area designated as Biosphere Reserve by Unesco. The whole system dried out during a long drought period in the past decade (2006-2009) and a smouldering peat fire took place in 2009. The physical and chemical properties of sediments were significantly disturbed by the fire. To date, the ecological system has not fully recovered from the impact. We present a raw data collection of the chemical composition of soil, groundwater and surface water sampled over four consecutive years in 2006-2010. The data include major and minor anions and cations, nutrients and heavy metals. Sampling points were located inside and outside TDNP both upstream as well as downstream. The information provided can be used to analyse the medium and long term impact of drought and smouldering fire to the TDNP environment. It is also a baseline for hydro-ecological modelling of the impact of climate change in arid and semiarid wetlands to develop adaptive management strategies.