Interestingly, growing up, I thought a second set of pipes for "non-potable" or reclaimed water was standard. Where I grew up in Florida, every lawn was watered with reclaimed water. According to their website[1], Florida is currently reusing 660 million gallons of water per day. Really makes me wonder why states that are in apparent perpetual drought condition haven't adopted similar techniques.
Non-potable is the industry term for "non-human drinkable".
And yes, the cost of that would be huge, not just in cities. In the UK the decision the victorians made to not have separate sewage and rain water drainage systems still has a knock-on today and costs a vast amount in water treatment, but the cost of separating rain runoff and sewage is still seen as prohibitive.
edit:
However, on a small local-scale grey water systems can do a lot of good, both for re-use but also rain water capture and re-use would help with flood prevention. If houses captured rainwater for use for lawn watering and other appropriate uses, this is something that could be done without great expense.
I believe most gray-water systems are internal to individual buildings.
For example, a house would fitted with a storage tank for shower water, which is then used for flushing the toilet, or even watering a yard. The toilet water is sent to city sewer system.
Water based toilets and watered lawns aren't used in places with shortage of drinking water. (Except in places with high inequality where an upper class can afford to use water in toilet but lower class can't afford to drink it)
gambiting|10 years ago
Vendan|10 years ago
[1] http://www.dep.state.fl.us/water/reuse/
eterm|10 years ago
And yes, the cost of that would be huge, not just in cities. In the UK the decision the victorians made to not have separate sewage and rain water drainage systems still has a knock-on today and costs a vast amount in water treatment, but the cost of separating rain runoff and sewage is still seen as prohibitive.
edit:
However, on a small local-scale grey water systems can do a lot of good, both for re-use but also rain water capture and re-use would help with flood prevention. If houses captured rainwater for use for lawn watering and other appropriate uses, this is something that could be done without great expense.
mason240|10 years ago
For example, a house would fitted with a storage tank for shower water, which is then used for flushing the toilet, or even watering a yard. The toilet water is sent to city sewer system.
fulafel|10 years ago
wehadfun|10 years ago
kwhitefoot|10 years ago