Signs they may be present include experiencing a large number of wasps or bees around your property which could indicate a nest is nearby, identification of a nest or being stung by a wasp or bee itself.
Wasps enjoy a high humidity environment, they can build nests outdoors and indoors if they can gain access and are commonly seen in wall cavities and roof spaces. Being stung by a wasp can be painful and in some cases life threatening to anyone who is allergic to stings.
Depending of the species being treated, options for treatment include a dust or chemical spray method. If a wasp nest is spotted you should not attempt to remove it yourself until the treatment takes place or you have spoken to a qualified pest technician.