Two species of rat live in the UK. The common rat or brown rat (rattus norvegicus) is the one we usually encounter. The adult rat is fairly substantial, weighing up to 500 grams and typically 200 to 270 mm long.

Its fur can be brown, black or white, but is most commonly grey. Its tail is thick and leathery and is shorter than its head and body. The ship rat or black rat (rattus rattus) is much less common. It is darker, slightly smaller but with a longer tail and more agile.

Rats live for up to a year, during which time a female typically breeds five times. The average size of a litter is between six and 10.

Where you might find them

Common rats are widespread in cities, usually in sewers.

Sometimes they dig a complicated tunnel system with several openings on open land including embankments, rubbish tips and gardens. Although rats are generally most active at night, they also forage for food and water during the day.

Health hazards

Rat-borne diseases include Weil’s disease (a rare infection which starts with influenza like symptoms and can be fatal) and salmonellosis (a food-borne illness causing diarrhoea and vomiting).

Structural damage

Rats cause structural damage and fires by gnawing through electricity cables and pipes.

They can burrow under building foundations and damage drains and sewers. They eat and contaminate human food which, if plentiful, will be only partially eaten leaving the bulk contaminated and needing to be destroyed. They contaminate food with their droppings, urine and hair. You must not ignore an infestation and or leave it untreated.

Prevention is better than cure

Make sure that your premises are in good repair. Seal any gaps around pipes going through walls, repair broken air bricks, check and repair defective or faulty drains and never leave drainage exposed or manholes open.

Deny rats food and water by clearing up food spillages and disposing of waste responsibly. Bird food can easily support a family of rats, so use a rat-proof bird table.

Rats need to drink on a regular basis, so don’t let water gather in seed trays and flowerpots. Clear areas that may offer shelter or nesting such as piles of timber or any overgrown areas of garden.

Getting help

If you have a problem with rats you need the help of a professional pest controller. Rats are difficult to treat on your own.

Get information on fees and charges on our pest control homepage.


Call us on 020 8753 1081 or email environmentalprotection@lbhf.gov.uk.