An automatic control for a kitchen and/or lavatory faucet can significantly reduce water consumption through intermittent operation. Because so many of the functions that faucets are used for also require the use of an operator, using a hand to also operate the water flow can result in wasted water between the time that a hand moves from lever to the next object or task at hand -- a bar of soap, pot to fill with water, or dish for rinsing. There are many technologies to control the flow of water that do not require a hand for operation. These include self-closing valves, motion sensors, metering, and push-activated (by foot or knee) devices.

Automatic water supply devices can also eliminate cross-contamination by keeping hands (and germs) away from commonly-used surfaces. Hands-free washing after handling unsanitary foods such as raw meat allows germs and mess to wash down the drain instead of clinging to the faucet handle. In addition, both hands are freed to hold heavy pots or multiple items and perform kitchen tasks more safely.

There are many configurations of automatic valves. Faucets that operate by sensing movement when an infrared beam is interrupted are in wide use commercially. Residential designs are available or an infrared sensor can be retrofitted to an existing faucet. Knee and foot operated levers control faucet flow by a valve in the supply line(s). A mixing loop can control the temperature of the water that is delivered by some of the lever operated models.