Areas across the UK have been hit by localised flooding after weeks of wet and mild weather were followed by heavy rain in January.
The British Pest Control Association (BPCA), is urging householders to take preventative steps now to avoid the risk of an infestation.
Dee Ward-Thompson, BPCA technical manager, said: “Each year winter weather forces some rats to seek warmer, indoor spaces near a source of food, but flooding can drive even more rats out of their burrow, forcing them to find a new place to nest.
“Rats are strong swimmers and are capable of 72 hours’ non-stop swimming in their search for a new home.
“They can travel along flooded drains, surviving even the most aggressive weather conditions, which is a definite concern from a public health perspective.
“Rats may use pipes, as well as unscreened vents or gaps in the eaves and roof edges, to gain access.
“Rats are exceptionally agile and despite their size, even adult males can get through gaps and crevices as small as two centimetres.
“Once inside they will head under the floor or find a warm space to build a nest in the walls or loft.”
BPCA recommends householders plug any gaps, holes or crevices in exterior walls in a bid to prevent rats gaining access in the first place.
Drain covers should also be checked to ensure they fit properly and disused pipes sealed off.
For more information about pest problems, or to find a BPCA member, visit www.bpca.org.uk/find.