There may not be one. You may have to shut the water off where it comes into the house or at the water heater. If there is one under the sink, it should be fairly obvious. Follow the supply line from the faucet.
Looking at it, it should be on the left, but it doesn't have to be. If there is a dishwasher line, that would be the hot.
Are you talking about pipes under a slab here? If so you probably have a hot water line under the slab leaking that is heating the water in the cold line.
Valves under the sink NO WORK HUH?
Dishwasher line is hot water. Tie ice maker into 1/2 inch cold line going to kitchen sink.
If there is no vent off the kitchen sink you would need to install an in-line vent.
Kitchen sink and washer use same drain line. Drain line clogged causing backup of drainage from washer into kitchen sink. Have drain line unclogged to take care of problem. If drain line not clogged, check for proper venting of drain lines.
The kitchen sink is the farthest appliance from the water heater. Have a plumber install a circulating pump under the sink for instant hot water.
It is where the supply line is attached to a water line. May be under the kitchen sink or in the basement under the refrigerator in the closest supply line. Should be a hot water line. Hot water because most of the minerals stay in the water heater and the water in the supply line will be cold from sitting. Someone may have put a shutoff at the floor behind the refrigerator, but I doubt it.
Kinetico does make compact water softeners that will fit under the sink. Here is the website for further infomation: http://www.kinetico.com/
Hot water is dripping under my kitchen sink. Should I call the plumber company, or should I turn off the water and try to fix it myself?
Under the kitchen sink.
It sounds like the water heater is so far from the kitchen sink that a recirculating line may be required to keep the line feeding the sink hot, otherwise, it will cool down causing you to have to run all that cool water out before the hot gets there. The reason you get it faster when you run the bathroom is because you are drawing more GPM through the line with two fixtures on.
A fitting made specifically for dishwasher that goes in drain line under kitchen sink.