While prepping to install a new kitchen faucet, I went to shut off the water supply to the house since there were no valves under the sink. I mistakenly chose to turn the city-side (gate valve) supply off instead of the home-side (ball valve). When I started turning, water began leaking from the stem. Doing a quick google of this let me know that I needed to tighten the packing nut. Never having done this before, I started tightening the wrong thing, which caused THAT to start leaking as well.
This 'wrong thing' is a second opening at the bottom of the valve. It's supposed to be closed off with a cap that just screws onto the thread. Tightening it caused it to leak. At this point I called a plumber and he said I could take care of this myself and told me the packing nut was my problem and how to tighten it. He called this other thing at the bottom a petcock. After getting off the phone, I followed his instructions and was able to get the valve stem to stop leaking and get the water turned off.
The 'petcock' is still leaking even with the valve closed all the way. If I try opening the home-side valve, water jets out of the petcock. The same thing happens if I try opening the city-side valve that I successfully got closed. I tried tightening the petcock cap more and ended up breaking it. It wasn't doing anything to stop water leaking anyway.
What the hell is going on here? It looks like I'm going to have to deal with this small leak until the morning when I can call a plumber. The city will likely have to come shut the water off as well.
Can anyone help me out with this in the meantime?