Water comes out of my over flow copper tube. What do I need to do to fix it?

There are several reasons a temperature and pressure valve would discharge. The first being that your water's so hot it turned to steam and the pressure opened it up or the temperature of the water rose to the point that the valve begain to release water. However, most T&P valve failures are due to a spring inside the valve that has weakened. If your water isn't overly hot try this. Spray some WD40 on the shaft just under the lever and then work the lever up and down to let it work in. If that don't allow it to seat and quit leaking then the valve itself is faulty and must be replaced. Hope this helps you out. Cheers, Tom

The over flow valve (pressure safety release) is probably bad. Happens quite often. Replace it.