How do tap water pipes stay clean for years


I’ve been drinking tap water all my life and I have to wonder: Tap water pipes have a lifespan of 50 years, without any regular cleaning and maintenance. I have to clean my aquarium every week and even after cleaning it I wouldn’t drink from it. I know light and air play it’s role, but still, 50 years? Is the inside of the pipes really staying that clean or is it that the dirt in there doesn’t really bother us?

In: Engineering

Sorry to burst your bubble dude, but they don’t stay clean. Just google “inside of water pipe” and be prepared for some horrification.

There has been research that indicates that the “disgusting” biofilms that line the inside of water pipes actually purify the water.

>“Our drinking water is to a large extent purified by millions of ‘good bacteria’ found in water pipes and purification plants, Swedish researchers have found. So far, the knowledge about them has been practically non-existent, but this new research is about to change that,” according to Lund University in Sweden.

>Researchers at the university “discovered that bacteria and other microbes are found in the form of a thin, sticky coating in drinking water treatment plants and on the inside of water pipes. Known as a ‘biofilm,’ the coating is inescapable because every surface involved in the process of getting drinking water to your tap is covered in it,” RT recently reported.

If you think about it, it makes sense. Biofilms are communities of microorganisms that cluster together and stick to the pipes, for them to live, they need to feed, and pure water isn’t particularly nutritious, so they would surely be pulling stuff out of the water to feed on it.

water in pipes (not in your house) are constantly moving which makes buildup more difficult. the water is treated and kept a specific ph. a bit of mineral deposit is acutally good and is why lead pipes are still in use. slight mineral build-up acts as a barrier between the water and the pipes and lead pipes generally aren’t an issue. the issue arise when the pipe is “too clean”. the mineral deposit being dissolved or physically break off would reveal the lead pipes leading to the health issues of lead.

the impurities in water is why its conductive. distilled water (water with no impurities) does not conduct electricity

Most water systems are required to implement corrosion control. Use of a phosphate chemical that both coat and sequester metals in the water. Ph/alkalinity are also implemented. Biofilms are generally not wanted and a problem in the summer months. Hydraulic swings in flow can cause slothing away. Also can cause a big chlorine demand but im no expert on biofilms. Will read the other post on how its good in drinking water. Contrary to believe that water is always moving it really depends where your tap is. We have night time flushers that go around at night and open up hydrants in the “dead” spots. We also are constantly testing the chlorine residual in the tanks and will take them out of service and shock treat the tank with high free chlorine to reduce the biofilm. Each system is different and has its own unique chemistry. Any change has to be taken very seriously. Like Flint they changed source water and I dont believe they used any phosphate for corrosion control. Google langelier index corrosivity. Also, I work at a treatment plant but am no expert on the distribution system.

The big difference is that the water in the pipes changes. In your tank, the water sits there for a week. Okay, it moves about and gets filtered, but it’s still very much the same water. Plus, you’ve got fish there, you put food in, they poop it out. Meanwhile, in a pipe, the water is basically constantly flowing, there aren’t any fish, and nobody is feeding them. So the water is fresh, not semi-stagnant

Depends on the pipe and water quality. Hard water will build up in the pipe over years depending on the pipe material.

Edit: I’m a Journeyman plumber

Water treatment engineer here. In the US, our drinking water plants provide just enough chlorine to have a small residual (0.1-0.5 mg/L) by the time it hits your tap. It keeps the pipes clean and is a low enough dose that it isn’t carcinogenic to humans.

Europe doesn’t allow this (not saying if that’s good or bad) as they use UV disinfection mostly for water leaving their plants. The age of your pipes can also be a big deal and what they were constructed out of.

This. Flint cut back on both phosphate for corrosion control and reduced chlorination to save pennies in their budget. That was almost as as big a problem as going to a less trustworthy water supply. A well maintained distribution system solves most of the issues the OP mentioned. Flint is a case study on how bad things get when you cut back on very basic public health policies.

The insides of pipes don’t stay clean. Cast iron pipe get a continuous build up of deposits (do a google search for build up on cast iron water pipes). Cities conduct continuous maintenance on pipe infrastructure – providing potable water is a significant part of the city’s budget. Also, potable water is cleaner than you fish tank water.

>I have to clean my aquarium every week and even after cleaning it I wouldn’t drink from it.

Think about how clean your aquarium would be if you cleaned it out several times a day. Every time you wash your hands in a sink, wash dishes, flush the toilet, take a shower you are changing out the old water with new water.

Good bacteria clean out water. Just like you’re fish tank, they’d good bacteria that keep it healthy for your fish. Only change their water once a month and only 25%, or fish will be less healthy.

humans forget stuff and turn it into stupid silly things that make us forget why stuff is done, even at the risk of survival.

example: why was there ever a “wishing well”? it seems that at one point in our collective history, a village would have been getting the water from a common well. COPPER and SILVER purify water to some extent. throwing copper and silver pieces into your well would help to clean the water and hopefully boost it on its way to “potable/drinkable”.

sailors, (think giant tall sailing vessels of the 1400’s..) would commonly put silver in the barrels that are for containing the water for the sailors survival in order to help keep it from going to a non-useable state.

so … copper pipes. at least, that was the premise afaik. now that we use oil–> plastic, a lot of places need to put in a water filter, which, mostly, run the water through silver. (ie: []( )

copper pipes will oxidize eventually and need to be replaced due to small “pin-sized” holes, about 50 yrs. ….

Most domestic water pipes are made of copper or an alloy of copper. Certain metals like copper, and galvanized steel have inherently antibacterial properties

Its because water is constantly flowing. Its the same reason running streams make for drinking water, and the same force behind water shaping rocks into smooth surfaces.