# Water System



## Whisper (Mar 31, 2013)

I was wondering if anyone knows how city water system works. I'm not looking for a detailed description, just basic and if a house in the city with no power can still have water and if so, for how long.


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## Olly Buckle (Mar 31, 2013)

When the water has been purified and chlorinated it is usually pumped to a tank on a tower situated in a high place. This means gravity supplies the pressure to the pipes and the flow should continue as long as there is water in the water tower making the supply impervious to power disruption at least in the short term. Basically it is necessary for emergency services like fire hydrants. If there is long term disruption and a potential shortage the domestic supply will be turned off and standpipes, basically a simple tap, installed on a neighbourhood or street basis,are installed. People use a lot less water if they have to queue for it and carry it home from the end of the street.


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## Whisper (Apr 1, 2013)

Thanks. I've been doing some research on this today and this is spot on.


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## Olly Buckle (Apr 1, 2013)

You will probably start noticing the towers now, they have to be pretty solid to support the weight but the designs vary hugely, or over here they do. The Victorians built them mock Gothic or Norman castles.


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## Nickleby (Apr 1, 2013)

Olly is correct. I'd just like to add a couple of points.

In a dense city such as New York City, each building will have its own water tank on the roof. The utility typically pumps water into them at night, when their equipment is not as busy, so that they're full in the morning. In an emergency, an enterprising tenant could close the main valve, so that the others would have to get their water directly from the tank, i.e. through him.

In a US suburb or residential area, a water tower will be located on a hill. The higher the tank, the higher the pressure at the other end of the line. You'll find valves at junction points so that a leaky line can be shut off without affecting the rest of the system. It takes power to pump water into those towers and rooftop tanks, so if the power grid fails, you're stuck with what's already in the system. After a while the pressure will decrease. There are devices called backflow preventers (BFP) that stop the water from reversing direction--if there's a leak in your neighborhood, you don't want the dirty water seeping into your house, so the BFP only lets water in if it's above a certain pressure. In other words, when the pressure gets below that point, the house's plumbing is useless. You can drain what's already in it, but you won't get any more until the system pressure returns to normal.

Any other questions, please ask.


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## Whisper (Apr 2, 2013)

Olly Buckle said:


> You will probably start noticing the towers now, they have to be pretty solid to support the weight but the designs vary hugely, or over here they do. The Victorians built them mock Gothic or Norman castles.




Its funny you should say that. Although I've always noticed them, I really didn't give them much thought. I always knew them as water towers, but at the same time, always thought of them as byproducts of a different era and they were only used nowadays to announce where you were on there side. I didn't actually realize they were in use. Now I do. I was studying the one that I drive by on the way home from work everyday and looked at it in a new light.


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## Whisper (Apr 2, 2013)

Nickleby said:


> Olly is correct. I'd just like to add a couple of points.
> 
> In a dense city such as New York City, each building will have its own water tank on the roof. The utility typically pumps water into them at night, when their equipment is not as busy, so that they're full in the morning. In an emergency, an enterprising tenant could close the main valve, so that the others would have to get their water directly from the tank, i.e. through him.
> 
> ...



Thanks for this. Between you, Olly and the research I've done, I've become an expert.


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## Morkonan (Apr 3, 2013)

I've had some limited professional experience with municipal water systems, basically working with certain sorts of contracts.

Water rationing is something you'll need to address if you're writing about a massive power outage. You'll also need to check to see what sort of protections the power company has in place to keep critical services functioning and even what the water treatment system may have in regards to certain backup measures. Of course, no sort of "battery-backup" will run a municipal water supply for very long at all and, AFAIK, there aren't any efficient solutions in that regard. Diesel powered electric generators may be enough to run pumping stations and I'm sure many have those already installed. But, it's a solution aimed at providing uninterrupted service, not uninterrupted _normal _service. Water rationing would obviously go into effect and might even be controlled, in dire situations, from a number of key pumping stations so equipped, once the gravity-feed tanks run dry. And, if there's a wide enough power outage to effect municipal water supplies, it's going to effect diesel distribution as well. Diesel tanks at gas stations will have to be hand-pumped, eventually, and supply chains would be seriously disrupted in event of a widespread outage, like a national emergency.

It could be possible that, when these factors are combined, you could maintain limited use water supplies for a municipality for a fairly long time. Water treatment, for the most part, is a physical and chemical process that, while requiring power, doesn't require anything severe. (Some systems are different, though.) Much of the mechanical work can be done using simple filter systems and chemicals, though, obviously, processing would not occur in the same sort of volume, so rationing would still need to be in effect. Eventually, in dire situations, the water company might run out of certain stockpiles of chemicals. Because of the nature of chemicals like sodium hypochlorite, which does not retain its potency for very long, they are not kept in inventory in any large amounts, but are kept in a just-in-time sort of manner. If that supply-chain fails, then the potability of the water might become an issue and users would be reduced to boiling it themselves, in the case of drinking water, even if the pumps could be kept running. (Those familiar with areas with spotty water service or when there has been water service problems have probably received "boil your water" notifications before.)

Providing water is not just about what comes out of the tap, but what comes into the municipal water system and how its handled, as well. Brown water, like storm runoff, is usually not treated and channeled directly to streams. Blackwater is... sewage filled with poo and other disgusting things and is always treated and then discharged. Greywater is everything else produced by a household, but is usually combined with blackwater in a municipal system. (Grey, black, brown... IIRC, those are the correct common terms when I was working with some municipal clients. Some "survivalist" and "eco-friendly" types try to recycle the grey water generated by their own household activities.) It's likely that your municipal water system will not treat then reintroduce any of this back into the potable water supply. Instead, their potable water supplies will come from aquifers, lakes, and the like, sometimes many miles away. (NYC has one of the longest systems, reminiscent of some of the aqueducts of the ancient world.) All of this stuff has to be pumped, for the most part, in and out of the municipal water system... Water supply may not be an issue, depending upon how complex its requirements are and what services can still run after _Everything Goes Dark_. So, you may not have any trouble giving your fictional citizens clean drinking water for a time. But, what are you going to do with the *poo*?


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## Whisper (Apr 3, 2013)

Thanks Morkonan,
This helps. In my story, 80% of the poputation is dead, so an over abundance of poo shouldn't be to much of a problem. Someone leaving the water running, on the other hand, is going to be a problem.


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## Nickleby (Apr 3, 2013)

To add a bit to these new topics ...

Most sewer lines are gravity lines, i.e. the pipes run downhill. Where a source doesn't have a downhill path to a line, you typically find a pump station that feeds a force main, i.e. the pump pushes (forces) the poo uphill until it gets to a gravity line. With no power, of course, those pump stations will stop pumping. Luckily, there are valves in place to keep the poo from running back down the force main and into your house. Until the power comes back on, you have a finite storage capacity in the pump station.

A larger question is, with only 20% of the people remaining, is there any point in maintaining all that infrastructure? The water system depends on maintaining inner pressure, not just to keep the water moving but to keep contaminants out of the inevitable small cracks. After a few days without any activity, the water inside the system will be just as dirty as anything outside, if not worse. Without constant motion, the sewage will clump up and block the pipes--that's actually a good thing, since it will prevent leaks. Storm drainage systems will clog, not immediately, but without maintenance they will eventually allow flooding in low-lying areas. With no electrical grid, the miles of wiring aren't good for much except the refined copper metal inside--but you've probably considered that already.


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## Whisper (Apr 3, 2013)

Nickleby said:


> A larger question is, with only 20% of the people remaining, is there any point in maintaining all that infrastructure?



Here's the thing. I'm not really looking to maintain the system. I just needed to know if, after my MC woke up after a lying on the floor covered in her own filith for most of a week, if she could hop in the shower and clean up if the electricty was off, or if she would have to use bottled water from the basement. In my first draft I have her getting the water, but in my discussions with a friend, he said he didn't think water would be affected by electricty. So I started my research and came here to ask and now, and as it turned out, I'll have to rewrite the scene in the next draft. I don't mind and this discussion has given me ideas for follow on scenes. 

So thanks for all the help and the ideas.


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## Lewdog (Apr 3, 2013)

She should be able to take a shower, but unless there was any electricity it would be cold water out of the hot water heater.  At least the water wouldn't be stagnate.  If you think about it, you only lose water pressure if there is a leak in the system somewhere, it's all based on pressure in the line from the place of origin.  If a great percent of the population is gone, the best thing would be to just set up water collecting tanks from rain water, especially if there isn't anyone that knows how to work the water treatment plant.  If the water isn't treated properly it could spread disease.


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## Morkonan (Apr 11, 2013)

Lewdog said:


> She should be able to take a shower, but unless there was any electricity it would be cold water out of the hot water heater..



Some types of gas water heaters don't require electricity, so it may be possible that hot water would still be available if the supply of natural gas hadn't been cut off.


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## tabasco5 (Apr 16, 2013)

Whisper said:


> if a house in the city with no power can still have water and if so, for how long.



Water and power are two separate entities.  You can have power without water and vice-versa in every situation I have ever come across (in America).  As for the length of time, I would think as long as you are paying the bill you would have the water.  

In your story example, it would really depend on the physical condition of the water lines and other infrastructure factors.  Theoretically though, the water would still be there as long as there is pressure and water available.


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