Farms more concerned with social responsibility and environmental protection should not underestimate potential risks related to the dispersion in surface waters and soils of oil and agrochemical polluted waters, deriving from external washing of agricultural equipment. While it is largely established that internal washing waters of sprayers’ tanks are reused on the same soil and crop on which a given agrochemical is permitted, much less frequently the same applies to the so-called “external washings”. They are generally a mixture of washing water, agrochemical contaminated soil particles which stick to the equipment, diesel and lubricant oil residues. For the proper treatment of these “washings”, a project is starting at Fattoria Autonoma Tabacchi of Città di Castello, under the scientific reference of INSTM. An off-set biobed will be built where washing waters enter, after physical removal of oil residues. The agrochemicals are those labelled for tobacco and its rotation crops. This biobed uses materials commonly found at the farm level: soil, de-watered digested phase, cereal straw, and coconut fiber-enveloped drainage pipes. A Lolium sp. and Festuca sp. turf will be overseeded on the biobed, to increase contaminated water infiltration and detoxification. After turf establishment, washing waters will begin to be sprinkler irrigated onto the turf whenever there is external washing of agricultural equipment. Two sampling wells will be built: one after the oil removing equipment (Enter Well), which will be operated also as a temporary storage tank before sprinkling, and one at the end of the biobed (Recovery Well). During the experimental period well waters will be sampled and multi-residue analysed every 21 days. Tests in similar plants, operating for 4-5 years, have indicated that this kind of biobed works very well on the agrochemicals commonly used by growers, almost reducing agrochemical residues below detection limits in the recovered leachates.