SWM Öko-Bauern Programme — Mangfall Valley Organic Farming for Drinking Water Protection (Germany)

Munich draws its drinking water untreated from natural springs in the Alpine foothills, most importantly the Mangfall Valley about 40 km southeast of the city. Because the water reaches consumers without filtration, protecting the quality of the source catchment is critical. In 1992, facing rising nitrate pollution risk from intensive farming in the valley, the municipal utility Stadtwerke München (SWM) launched the Öko-Bauern ('organic farmers') programme.

The logic is a classic avoided-cost PES: it is cheaper for the utility to prevent nitrate contamination through land-use change than to build and operate treatment infrastructure to remove it afterwards.

SWM pays farmers within the catchment to convert to certified organic farming — working with the Naturland, Bioland, Biokreis and Demeter associations — under contracts running 18 years, covering income losses during conversion plus ongoing advisory and certification costs.

185 farms have converted since the programme began, and roughly 4,650 hectares are now farmed organically in the Mangfall catchment, one of the largest contiguous organic farming areas in Germany. Munich's drinking water continues to meet the Drinking Water Ordinance's limit values without any dedicated nitrate-removal treatment step.

Published sources reviewed do not include an independent time series of nitrate concentrations before and after the programme, nor a formal counterfactual cost comparison against a hypothetical treatment plant. Even so, comparative academic case-study literature treats Munich alongside New York City's Catskills watershed programme as one of the two best-established reference models for municipal-utility watershed PES, and the scheme has run continuously for over three decades.