With a good valve, water temperature shouldn't change abruptly as you adjust from cold to hot. In addition, to prevent burns, particularly to children in bathrooms, a scald-guard or temperature-limit feature is offered by several makers for single-control faucets. With these, you can remove the handle and adjust the maximum water temperature the faucet will deliver-a wise feature if you have small children (most plumbing codes now require these types of valves in new residential construction). For water conservation, all new faucets are now mandated to deliver no more than 2.5 gallons per minute; some provide additional adjustable flow rate restrictors.
Warranties vary. The best ones offer lifetime protection against leaks and drips, insuring that your faucet will provide years of trouble-free service.
