You are never alone – not even in the shower, where tiny living microbes are huddling in the pipes, waiting to join your wash.
That might be a little creepy or a little gross, but if you are Dr Rob Dunn, a North Carolina State University biologist and author of Never Home Alone, it’s a bit of both – and pretty fascinating.
Dr Dunn studies all the tiny living things everywhere, including, recently, in your showerhead.
He and his team conducted the largest study of showerheads to-date, during which they surveyed bathrooms the world over in search of the cleanest – and dirtiest – water we bathe in.
They are interested in the bacteria that live in all water systems and stick to our showerheads.
It turns out that the harder we try to cleanse our water supplies of microbes, the more of the nastiest kinds we wind up having in our showerheads.
And really, Dr Dunn says, the benefits of a wilder microscopic world in the bathroom might suggest our lives would be a little healthier if they were a little dirtier.
Showerheads may be the culprits of a growing number of myobacteria infections in the US – and the more heavily the water supply is treated, the more potent the bugs in your bathroom
It’s early morning, the sun is barely up, your eyes are practically sealed shut with sleep.
But a warm shower, and a strenuous scrub have you just about set straight, feeling purified and enlivened.
You turn around, turn off the water and, head still tilted back in enjoyment, you open your eyes.
And then you see it, the filthy-looking, grimy, discolored source or your cleansing: your showerhead.
If it looks to you like something is alive on there, then you’re right.
‘There is going to be life in your showerhead, it’s something you have very little control over,’ says Dr Dunn.
‘Though, that probably doesn’t help you much when you’re in your own apartment as you confront your own showerhead,’ he admits.
Alongside other microscopic creatures like single-celled protazoa and, in some places, tiny crustaceouns, a group of microorganisms called nontuberculous myobacteria (NTB) are inevitable in water.
NTB aren’t meant to live in human bodies, but they sometimes make their way from the water source into our bodies.
They can be dangerous to people with weakened immune systems, though they are rarely harmful to healthy adults.
You’re going to be showered with life … it’s something you have very little control over
Dr Rob Dunn, North Carolina State University biologist, author or Never Home Alone
Still, myobacteria don’t really want to be in us, we don’t really want them there and, strangely, scientists have seen a mysterious uptick in myobacteria infections, particularly in the US – though annual rates remain low and poorly reported.
But these rates and increases vary quite widely from state to state, and that raised some questions for Dr Dunn and his colleagues.
‘Myobacteria are funny, because we’ve had very little understanding of why they are becoming more common and why they vary a lot from place to place,’ he says.
‘And there’s more and more evidence that showerheads seem to be, in one way or another, the culprits.’
If you unscrew your showerhead, inside the pipe that feeds it, ‘you’re always going to see a little gunk on the pipe itself,’ says Dr Dunn.
That ‘gunk’ is what scientists call biofilm, excretions that water-dwelling microorganisms use to keep themselves planted firmly in their preferred habitats.
Or, as Dr Dunn puts it in his book, ‘the bacteria poop a little indestructible condominium in your pipes, built of hard-to-break-down complex carbohydrates,’ he writes.
‘But when the pressure is high enough, these species are let loose into the fine aerosol spray of water droplets pelting our hair and bodies and splashing up and into our noses and mouths.’
This seems to be a more common issue in states like Texas and Florida, but not so much in Michigan.
It’s also more common in the US than in Europe.
Dr Dunn and his colleagues had thousands of people all over the world swab the insides of their showerheads to see what was different where.
Ancient [unfiltered] water is doing a lot of what we’d like our systems to do. Nature’s checks and balances are working in our favor … if we don’t screw up things
They found that across the board, well water – ‘ancient water,’ Dr Dunn says – drawn up from deep underground and rarely or minimally treated yielded the most diverse microorganism populations, but had less dense populations of myobacteria.
In urban areas where the water was treated with chlorine to try to make it more sterile, however, there seemed to be less diverse life, but more myobacteria that could make us sicker.
Essentially, the chlorine in treated water kills off lots of less tolerant microorganisms – harmful or not.
But the tolerant ones, which tend to become the most potent and hard-to-beat bacteria, can tough out the chlorine and beat other life forms that might compete with them.
Ironically, the plastic showerheads that can look so gross so quickly can actually help to bat back the strong myobacteria.
‘Plastic is a little biodegradable, so other bacteria can eat a little plastic and compete with the myobacteria,’ Dr Dunn says.
‘Crappy yellow tube hardly ever seems like salvation,’ but in this case it is.
It’s salvation to the other organisms that eat myobacteria, and perhaps to us, too.
Dr Dunn explains: ‘All water you drink has life in it. It has fungi, protozoa, crustaceans. We want to figure out how to get rid of stuff that can harm us, like fecal-origin pathogens and myobacteria.
‘Ancient [unfiltered] water is doing a lot of what we’d like our systems to do. Nature’s checks and balances are working in our favor … if we don’t screw up things.’
Is that really what we want to be? just sealed in with our own falling-apart every day?
He says that letting a little outdoors indoors could be the best thing for us, because what we call ‘clean’ really isn’t.
‘One surprise is that most clean houses are not sterile, because they just become dominated by just human body microbes,’ Dr Dunn says.
This is true for the space station, which isn’t really ‘clean,’ Dr Dunn insists, ‘it’s just full of bits of astronaut being biodegraded. Similarly the top floor, sealed-off penthouse is not the most sterile place – it’s just the most human one.’
For him, that raises questions that are ecological, biological and even existential: ‘Is that really what we want to be? just sealed in with our own falling-apart every day?’
Dr Dunn’s theory is that once we learned that some of the invisible living things in our environments could kill us, we went a little overboard and figured we were best off killing everything.
Add into that mixture a post-World War II mentality (‘if it can kill the enemy on the battlefield, it can kill the enemies in your home!’) and commercialism (‘kills 99 percent of germs!’) and we were ready to obliterate all bacteria.
‘Everything kills 99 percent of germs … but really what you want to kill is about 50 percent,’ says Dr Dunn.
‘But as we’ve sealed ourselves indoors we’ve lost exposures to microbes that we need to be healthy … it’s clear we broke something, though it’s not clear how, and we’re starting to see ways we might reduce the symptoms if not fix it.’
Studies have already shown how a little farm dust can help a city kid, or that children who grow up with a dog have better immune systems.
‘We need to start reacquainting our selves with the outdoors, opening a window and letting a little more nature back in,’ Dr Dunn says, or even letting the grime grow in the showerhead.