What lurks beneath the surface? What is underneath, where eyes cannot see? Is it something valuable? Is it something old? Is it some treasure or something frightening to behold? These are common ...

The failure to do routine maintenance on a key gate valve in the Hetch Hetchy water system contributed to the crisis that briefly cut deliveries in half last month, San Francisco's top utility ...

Q: I had to turn off the water supply valve at the top of my water heater. So I turned it, but it kept on turning and turning without shutting off the water. A neighbor of mine said it is a gate valve ...