[Pilotincmd]

I tried to turn off my main water valve and it only slowed down the water . When I tried to turn it back on I. Keep turning valve but no effect. Water won't turn back on.

[Stratmando]

Handle may be stripped, try tightening screw or remove screw and handle to determined if stripped.

[massplumber2008]

Hi Pilotincmd

Grab the stem with a pair of pliers and spin the stem... may take many turns, but may work.

Otherwise, it sounds to me like you have a GATE VALVE (see image) type of shut off and most likely the valve has broken at the grooved stem and will need to be replaced. If you are on city/town water you'll need to contact them to get the water shut down so you can make the repair. If you are on a well system, shut it down and replace the valve. I'd remove the old valve and install a new BALL VALVE.

If you can't manage to get the water off tonight, or if there is an emergency charge for the city/town to come out, chat with a neighbor and see if they'll let you hook a hose up from your outside faucet to their outside faucet... cold will feed the water heater and give you hot water as well... ;)

Glad to discuss more if you want, OK?

Mark