Our hot water is in our den (which was our garage before). We are selling and they want us to fix the hot water heater overflow pipe to where it will not drain into the den if it does. How do we fix this and what do we connect it to?

It has to go outside or into a drain.

Okay since it is in the garage there is a concrete floor then we would have to drill thru the block to the foundation. Is this hard to do.

The best thing to do is empty the water heater and break the piping connections and set the water heater in a pan(these are available at home depot or plumbing supply houses). Run the drain (while maintaining proper pitch) from the pan along the wall, so it's not a trip hazard and is out of the way, and drill thru the wall at whatever elevation it ends up at. This way if the t&p valve is popping, the evidence will be in the pan. However, if you live in a cold climate, this will let cold air in in the winter time.

A pan will never drain a relief valve discharge without overflowing. The valve discharge should go out the wall and terminate at a point between 6" and 12" above the ground.

I know I haven't done this as long as you hj, but how many domestic water heaters have you seen the t&p discharge enough to flood a pan? Also by using a pan they will be protected against a tank leak that could go undetected for days or weeks.

All of them other than the occasional drip due to thermal expansion pressure buildup. When the valve opens, it is a full 3/4" stream of water under house preessure and there is no drain pan in existence that will drain that amounnt of water by gravity. The drain pan is strictly to handle a water heater tank leak, which hopefully starts as a minor drip.

Is it OK to drain the pressure release overflow into a utility sink? Thanks!

Yes it is okay to do that. However, you don't want too many elbows in the pipe.

Some areas will not allow it since the water discharges at almost steam temperature and someone could be using the sink at that moment.

Why not install a pan and look into installing or having installed a WAGS valve or FLOODMASTER system and then would avoid any problems.

take hj's advice and pipe it through the outside wall.

If you decide to run outside put the relief valve in a larger pipe and indirect it into it. It could freeze over in the winter. Do not put the relief valve into a pan.laundry sink is ok in ohio.

In Texas, it was common to pipe the T&P line into the drain from the drip pan as long as a check valve was in line between the tee for the T&P and the pan; this is no longer acceptable and the line must exit the building, always have fall to it as a drain should have, turn down outside and terminate approx. 6" above the ground. There is no need to pipe it into a drain. I think in commercial aps. it may terminate into a floor drain.