Here's my problem, my main shut off valve inside the home (at finished basement) leaks I would like to change it out. It is a 45 degree angled gate valve. I was able to access my curbside shutoff which is about 2-3 ft. below ground surrounded by a 4in. Caste iron pipe. After shining a light down the pipe I can see that the shut off handle is up against the pipe. What can I do? What would a plumber do to change out that interior valve? Is there anything I can do that doesn't involve a backhoe to get to the curbside valve?

A backhoe to dig a few feet? Use a shovel, and see if that cast iron pipe can be removed. You could also ask the water company how they would go about getting to that valve. Wouldn't be surprised if they had a special tool to make it easy.

Me, I start digging.

I agree with Tal, if its leaking now.. its only going to get worse. I am assuming you snugged down just a little bit on the packing (don't torque it down hard or you WILL make it a lot worse) where the handle comes through and that didn't stop the leak. Sometimes that's all it takes.

Is it leaking at the packing nut or not closing completely? If it is the packing, tighten as Smoothy notes. I have also been able to remove the handle and packing nut and add additional packing even with the water on. If the valve won't shut off, it may be some debris in the bottom groove of the gate valve. If you decide to remove the valve, install an SS ballvalve.

You can do one of two things:

1. Call Water Co. and ask them to shut water off at the curb. Once you are finished with your repair, call them back to turn it back on. They have a way of doing it, and they should do free of charge
2. Do as suggested above: excavate it yourself. It is not that deep. Make it a Sunday project.

In any case, no matter what you decide to do, take care of it in timely manner. I would not sleep well knowing I cannot shut off water to my house should emergency leak happen

Hope that helps

Milo