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Honestly, I had always assumed Israel was much more advanced than this article points out. In the 90s I was a kid in the middle east. We had a "sweet water" tap in the kitchen for drinking. Everything else was recycled. We didn;t flush our toilets with drinkable water. And low-flow appliances were the norm. I find it shocking that Israel hadn't started such measures until 2007.

Israel has been recycling most of its wastewater since the 60's, today it reclaims over 86% of its wastewater this is a huge margin over the next closest contender which is spain at 17%. The water in the toilet is drinkable, that doesn't mean it's wasted there is no need to overcomplicate your water management systems if you can reclaim most of the water back and reuse it, including as drinking water. Countries with "dual feed" water systems don't do it for efficiency or water preservation, they do it because the main feed water quality is below drinking levels, so larger municipalities can supplement the main water system by providing a "drinking" tap into homes, in some places the drinking tap is communal for the building, block, or even the entire village while the rest of the water should not be drank without boiling or treatment if at all.

That isn't the system we had. The drinking water line supplied the "sweet water" taps and and dishwashers. Interestingly, the hot water tanks also got 'sweet' water as dishwashers often use hot water. The non-drinking water in homes was recycled water and was more heavily chlorinated, making it safe for bathing but not great for drinking. It wouldn't make you sick, but drinking a large amount could be uncomfortable. Then we had a third standard for irrigation of lawns and such. That water wasn't as heavily chlorinated.

That's pretty standard in emerging water markets, the chlorinated water was actually most likely not the recycled one (you do not chlorinate water that is not near drinking quality, if you do it to unfiltered reclaimed water you create really nasty chemical reactions), it's most likely water that has been collected or transported at least partially in open air systems and the chlorine is used as a antiseptic. The drinking water is the higher quality water that has been treated and is transferred in a closed system with higher quality control, while the water used for lawns is most likely the reclaimed water.

When you can reclaim most of you water and ensure quality control throughout the system you simplify it, have one water feed for residential use, and usually another for agriculture and industry. Reclaimed water even drinking quality is usually not put back into the tap because the cost of ensuring water quality make it unfavourable, it's used for agriculture and industrial uses, when it ends up again as drinking water it's often as filtered bottle water simply because you can then transfer the cost of the additional water quality control to the industrial users.

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