Berthod Berthod, set up in 1973, joined SERFIM Group in 2011. It specializes in operations in mountainous terrain for the laying of drinking water networks, sewage works and dry networks. It also installs drinking water tanks, both below ground and partly buried. Based at Grignon (73), its geographical area of operations (public works) is mainly Savoy. It has a payroll of 20 persons and posts sales of €2.6m.