Q: Why is running water down the sink, shower, toilet or gutter considered wasteful use? Is not every drop that is sewered or drained in Sacramento sent to the wastewater treatment plant, which, except for a small amount that evaporates, returns that water to the river from which it came? – Richard Vincent, Sacramento
A: Using excess water in these ways is considered wasteful for a number of reasons. First, the more any one person runs his tap or toilet, the less water is available for someone else in Sacramento to do the same. That’s because the city is bound by regulations on how much water it can draw from the river at any given time. It has storage in place to smooth out the highs and lows in everyday demand. But when river water is in short supply, it becomes more important for residents to conserve.
Second, all this water drawn from the river means less habitat for fish, like the salmon and steelhead that migrate all the way from the Pacific Ocean to spawn in the American River each year. If we have to pump less water from the river for human needs, it will mean more water for fish, wildlife and recreation.
In addition, evaporation is not a small factor. In the Sacramento region, research estimates about 40 percent of the water applied for landscape irrigation is lost to evaporation. This water goes into the atmosphere and does not necessarily come back to Sacramento. It is more likely to be blown across the Sierra Nevada before it can form as rain again, likely benefiting some other watershed.
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Much of the remaining irrigation water that drains through the gutters does return to the American and Sacramento rivers. But along the way, it picks up fertilizers, pesticides, motor oil and other pollutants that degrade the quality of river water and threaten wildlife and public health. That’s one reason it makes sense to maintain sprinkler systems so they don’t flood sidewalks and gutters.
The drain water that flows from inside homes and businesses is treated by the regional sewage treatment plant, then discharged to the Sacramento River. That treatment plant is paid for by local taxpayers and utility ratepayers. The less water that has to be treated, the less it will cost to operate the plant. In addition, the treatment plant does not produce water that is drinking-water quality. Some pollutants remain in that effluent, and flow to the river.