The purity of the water is tested regularly.

水的纯度定期检测。

《牛津词典》

They worried about the purity of tap water.

他们担心自来水是否洁净。

《柯林斯英汉双解大词典》

In fact, New Yorks municipal water for more than a century was called the champagne of tap water and until recently considered among the best in the world in terms of both taste and purity.

事实上，一个多世纪以来，纽约的市政用水一直被称为自来水中的香槟，它最近被认为是世界上口感和纯度最好的水之一。

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Across Europe the price of water has gone up along with higher European standards for the purity of drinking water and for the treatment of waste.

ECONOMIST: Profit stream

The big thing here is the ability to let the community take its own readings to build a bigger picture of water and are purity levels through online applications.

ENGADGET: AirBot and WaterBot help localize pollution data collection (video)

Stick one end in a body of water near your home and it will upload water purity information to the web via a built-in ZigBee module.

ENGADGET: AirBot and WaterBot help localize pollution data collection (video)