YOUNG: Just ahead – we’ll dig into an antiquated mining law – but first this Note on Emerging Science from Lisa Song.

In the heat of summer, droughts bring water rationing and limits on outdoor use. A new household sensor could soon detect every drip coming out of your pipes, making it easier to conserve water.

Professor Shwetak Patel from the University of Washington has invented a gadget that he calls Hydrosense. Like a water filter, it connects directly onto a faucet. A single Hydrosense device can detect water use from anywhere in the house.

It's all about pressure. When you take a shower or brush your teeth, the water pressure goes down in all the pipes, and Hydrosense measures the water flow in gallons per minute. The sensors can even distinguish between different water sources. Each time you turn on a sink, for example, the sudden surge of water sends a small shock wave throughout the pipes in your home. Every single fixture, whether it's the kitchen sink, bathroom sink, or dishwasher--has its own unique shock wave. The sensor uses these differences to monitor water use at various locations.

And what about that dripping faucet? The average American household loses 11,000 gallons of water a year from leaking fixtures. Patel is fine-tuning Hydrosense to find the source of leaks.

That’s this week’s Note on Emerging Science. I’m Lisa Song.