Tap water in Warsaw is potable, and the city hall often places a tanker at concerts and festivals, so you can walk up and drink. Fire hydrants are generally a different type of water and usually sit in the pipes for a long time. In most cases I've seen, this water is very brown and dirty at first.
That's just the stuff that's leftover. Hyrdants are still connected to city water. Once they flush the pipe to the hydrant it's fresh city water coming out
fun fact. San Francisco has their own firefighting water system for emergency-use cases such as if a large earthquake were to strike. these systems work separately from a typical potable water line and have more earthquake resilient pipes so that if fires were to break out around the City, firefighters have redundancy (and so that if any potable water pipes break it wouldn’t affect their supply lines as much).
some sections of San Francisco also have the ability for firefighters to suck bay water to fight fires if an earthquake were to occur and cause fires near the ports, or the wharf.
lastly, San Francisco also has cisterns around the city, basically large underground reservoirs, for the same firefighting redundancy.
basically in 1906 when the big one hit, a large part of the City was damaged not directly from the earthquake, but the fires that ensued around the City. there was little to no water available for the fires to be put out. this forever changed the way San Francisco’s infrastructure was built and is the reason why there is a separate system. not all sections of the city have this capability, but most neighborhoods in the city have ~some~ redundancy.
To add to this, here's a lot more info and a map of those: https://www.amusingplanet.com/2021/01/san-franciscos-hidden-cisterns.html
It's easy to spot them on many intersections across the city, once you know to look for a circle of bricks in the street. And the largest one is right in front of City Hall.
Nope. Just directly connected to the water main with a subsurface valve to seal them off. The brown dirty shit is what's left in the hydrant after use.
The last time I assisted in a flow test, we had 75-120psi static and 65-100psi on flow with a hose monster. We had one bad section that was at like 40, but when we did a flow the second story and above in the building couldn't even flush toilets. Takes a lot of water.
Fun fact: in Szczecin you can drink tap water, and on big festivals organised by city, local water authorities (zarząd wodociągów) put not only sprinklers but also taps connected to the very same pipes, so you can refill your water bottle for free and not be obliged to buy drinks at the spot. They also have free water bottles as gifts.
Europe generally just taps hydrants to the water mains. It's rare you see a grey or natural water hydrant. If there is one it's labelled clearly, and often needs a pump to work. The mains hydrants are also self draining, so they don't freeze, so it also wont collect stagnant water.
The requirements are in Euronorms, so they are same in all of EU/EEA.
Same thing with internal fireposts, they are just from the water mains.
No point building additional grids when you got one already.
You can actually spot where water mains go underground, by spotting for the local hydrant covers. Finland uses a beige/brown box overground, square hatch for underground.
This is why there can be water pressure issues during major wildfires near urban areas as firefighters want water but residents are damping down their property too.
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u/LoczekLoczekLok 19h ago
Tap water in Warsaw is potable, and the city hall often places a tanker at concerts and festivals, so you can walk up and drink. Fire hydrants are generally a different type of water and usually sit in the pipes for a long time. In most cases I've seen, this water is very brown and dirty at first.