Warning bands with indelible writings “Warning water pipe” and “Warning gas pipe”, provided with galvanized steel or stainless steel wires, suitable for the detection of underground pipelines and pipes made of polyethylene and/or non-metallic materials. The use of these bands avoids any possible damage to pipes when further digging operations have to be carried out, since they signalize their presence. They are made of low-density polyethylene and are available in different colours according to the different use.