Removing water and human waste safely from our homes, sewers are a vital part of our lives – that we might not appreciate as much as we should! While most of us prefer not to think about what happens deep in the bowels of the underground pipe network, there's more to our sewerage system than you might imagine.
Sewers are designed to handle human waste and water, but head underground and scrutinise the vast network of pipes and chances are you'll find much more than this.
Items that people shouldn't flush down their toilet, such as nappies, condoms, wet wipes and cotton buds, are all prevalent in sewers, but more unusual items have also been discovered by sewer workers. These include prosthetic limbs, false teeth, clothing, footwear and even larger objects such as a dead cow, a moped, a sofa and a mattress - begging the question how they got down there in the first place?
Large chunks of congealed fats and grease, known as fatbergs, are also commonly found in sewers, with a whopper of a beast recently unveiled in London, measuring 250 metres and weighing 130 tonnes.
Anything that shouldn't be in the sewers can cause an obstruction, potentially causing water to back-up and flood into homes. It costs local authorities around £70 million every year to remove 300,000 blockages caused by items that shouldn't be there.
Rats in sewers
Other unwanted residents in our sewers are rats. It's estimated that there are at least 200 million rats living in sewers in the UK. These sewer rats, also known as brown rats, street rats or Norway rats, happily live in the underground network of tunnels, where they can easily move about, forage and breed. As creatures of habit, sewer rats establish and explore trackways through pipes, which they mark with their urine.
Sewer rats are tough and resilient creatures. They can go without food for four days and survive being flushed down a toilet. As strong swimmers, their legs make great paddles and their long tails serve as rudders for steering. They can tread water for up to three days, swim for up to a mile and hold their breath for three minutes.
Populations of sewer rats converge near urban areas, as there's more food waste for them to consume that collects near drainpipes. If food sources dry out, rats will even eat faecal matter.
With their hinged ribcages allowing for easy movement through pipes, it's not unheard of for sewer rats to find their way into your toilet bowl, although, thankfully, this is a rare occurrence!
A bad reputation
Rats are easily one of the most despised creatures on the planet - and it's easy to see why. Associated with transmitting diseases to humans, such as leptospirosis, rat-bite fever and salmonellosis, they also have a bad reputation for gnawing through wiring and causing electrical faults. Did you know, rats are also thought to be responsible for depleting a fifth of the world's annual food supply?
Rats have also long been blamed for spreading the Black Death plague during the 14th century and the Great Plague of London in the 17th century, by carrying fleas with harmful bacteria that bit humans. However, recent studies have suggested that it was more likely human fleas and body lice that were the culprits, as opposed to rats.
Some people even argue that sewer rats provide a useful role by consuming waste that would otherwise contribute to blockages.
Rise of the super rat
The average adult brown rat measures around 40cm in length and weighs about 350-500g. Recently, there has been an increase in sightings of rats much bigger than this, often resembling the size of a cat or small dog. In particular, a large rat measuring four feet long was discovered near a children's playground in London.
Some scientists claim these so-called super rats are increasing in size because rodents are becoming immune to poisons. A researcher from the University of Leicester even claims that super rats could one day become bigger than cows - ooh, I don’t expect any of us are looking forward to that!
If rats or other unwanted residents are causing problems in your network of underground pipes, you can trust Exjet to remedy the situation with their expert range of sewer services.