The authors discuss peculiarities of engineering geological surveys of contaminated urban and rural soils. The authors provide examples of the influence produced by the scope and composition of geological engineering surveys on the reliability of foundation soils. The authors also provide their assessments in terms of deformation-related properties of filled soils and their employment as immediate foundation soils for a residential house in Marfino. The article is polemical, and it may raise animated discussions of the problem. The authors believe that geological engineering tests held in urban areas and preceding the implementation of any construction projects should not be limited to cone penetration and field tests of soils limited to the grid, and at the stage of the project design, any tests shall be held within the perimeter of a designed building according to the effective legislation. In the course of field tests, geologists must pay special attention to the identification of contaminated soils of different origin, especially if the foundation is made of plates. The depth of the contamination may reach 10 meters in Moscow and in the Moscow Region. Identification of backfill soils may be particularly difficult.