The most important Berlin running and still waters were analyzed by a Quality Measurement Program of the Berlin Department of Urban Development and Environmental Protection, Department IV. One-hundred and fifty sites were tested; once a month in West Berlin, and about every 14 days in East Berlin. Measuring sites in areas surrounding Berlin were represented by data from the Water Quality Measuring Network of the Environmental Agency of the state of Brandenburg. Tests were usually made every 14 days. Samples were taken from the center of the body of water at a depth of about 50 cm and analyzed by various institutes. The range to which samples were investigated at various sites differs. The tests included chemical-physical, biological, bacteriological, and radiological parameters.
The maps use measuring data from 1991. The Map “Quality of Surface Waters” used results from 94 sampling sites in 99 measurement sections. The “Chlorophyll a in Surface Waters” used results from 59 sampling sites.