Why aren’t taps and pipes filthy on the inside?

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So kitchens and bathrooms need cleaned regularly. The moisture and food in these rooms specifically make it easy for pathogens to grow. Plenty of people get mould problems in their homes. Kitchens need cleaned with disinfectant sprays to make them safe to produce food in.

What about the inside of taps though? Depending on the age of your house, the pipes and taps could be decades old, and will have never been cleaned on the inside, yet we don’t think twice about pouring a glass of water. Why is this? How are the insides not full of rust, grime and bacteria?

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18 Answers

Anonymous 0 Comments

Mold comes from airborne spores. Mold needs air and food to survive. Inside of a water pipe there’s just pressurized water – no air, no food. Plus the water utility puts chlorine in the water so even if a little bug starts getting into the water through a tiny crack in one of the pipes, the chlorine will kill it.

You do get a build up of rust on the inside of cast iron pipes, through a process called tuberculation, but that doesn’t make you sick

Anonymous 0 Comments

The water that flows through fresh water pipes and taps is usually treated and is reasonably clean and free of pathogens.

Most wells tap fossil water from deep underground that is also free of pathogens.

So there’s few molds and bacterial present. The water pressure tends to flush the insides of pipes clean, too.

Finally, many homes use copper pipes, a metal that is naturally anti-microbial and resists corrosion, and brass fittings, an alloy containing copper.
Copper kills most pathogens on contact so they cannot adhere to the walls of the pipe.

There are some modern plastic fresh water pipes (PEX) that can support biofilms, if the water source is contaminated.

Anonymous 0 Comments

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Anonymous 0 Comments

Well, they do have some. Most water from a non-well source (city water) has chlorine in it, and another chemical I can’t recall… These help to keep the pipes clean. Used to work in a lab that was experimenting with UV LED’s in faucets that would kill bacteria and such…

Anonymous 0 Comments

Let me introduce you to Legionella. It mostly happens in stagnant warm water (usually underused hot water heaters) but has been known to grow in dead pipes. Think plumbing renovations in which a branch is capped and terminated but not removed at the branch.

Pressure at the termination will keep fresh warm water with bacteria from getting flushed out of the system while still at harmless levels. Kinda rare but there are some cases where a terminated pipe became a cesspool of bacteria which ended up growing into the main branch lines, causing great harm and illness.

Anonymous 0 Comments

Flow and temperature will mostly keep things tolerably clean. I used to do legionella checks on water systems. Stored hot needs to be around 60 degrees C and cold below 20 degrees C. Obviously cold can get warmer if the ground gets warm in summer but those are the recommended safe limits, in the UK at least. If your hot is just on demand, no real worries as long as it gets hot enough. The other hazard is capped off dead legs of pipe, which can become reservoirs of legionella, so they should be cut back. Low use outlets should also be flushed for a few minutes at least weekly.

The other one that causes some concern is pseudomonas aeruginosa, but that’s really more a problem for care facilities with immunocompromised folks. That one lives in the biofilms that can coat pipes so we treat that with chlorine dioxide, the same stuff that the miracle mineral supplement idiots drink.

Anonymous 0 Comments

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Anonymous 0 Comments

There’s very little in pipes of treated water for bacteria as far as air and food. There’s also chlorine. But things can grow in them. Plumbing is designed with the assumption that water will be cycling through fairly often and not sitting still long enough to let it grow much. I site I used to work at actually had a design oversight that caused potential dangerous bacteria to grow in the water line. Specifically to an out building at the perimeter (the security checkpoint I worked in often). This happened because that building had a 1/4 mile plumbing run from the main building and used a higher diameter pipe than what was needed to seve 4 toilets and an employee break room that were only used mainly by the 3-5 security personnel stationed in that building. So legionella started to grow in the pipes and we were all warned about it.

Anonymous 0 Comments

chlorine and filtration

regular maintenance of infrastructure

regular monitoring of water quality

Anonymous 0 Comments

Because water runs through them often enough that most things that would start building up get rinsed away pretty quickly. Have you ever taken a dirty dish, put it in the sink, then turned on the water and watched how much of the gunk on the dish gets pushed away immediately, well that’s basically going on inside of the pipe whenever it’s turned on.