DUBLIN (CBS SF) — Even in the vehemently eco-friendly Bay Area, we still flush our toilets with drinking water.  But, two cities in the East Bay are making sure the water getting flushed down the drain doesn’t go to waste.

Purple pipes have been popping up in San Ramon and Dublin, signifying sources of reclaimed water being used to keep lawns growing, and common areas like medians and parks watered in the cities.

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You could call it green without the guilt.

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“It’s drought tolerant, as long as people flush their toilets, we have the source and we clean it up,” Sue Stephenson of the Dublin San Ramon Service District said.

Underground, the purple pipes are kept separate from drinking water. The district spent more than $20-million over two decades to finish the system.

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“It costs money, and it takes time and a lot of planning, but thank heavens we have it today,” Stephenson said.