Why is water coming from exhaust on a 1991 Chevrolet Suburban?
That is condensation due to the exhaust system being cold and the heat from the engine makes the exhaust system / pipes sweat. As the exhaust system heats up then that will stop.
Now you said WATER not antifreeze. If you had engine coolant running out of the exhaust then it would be the color of the antifreeze and it would be steaming WHITE and then you would have an engine problem, MAYJOR. You said water. Drive it you have no problems. That is normal.
Not much. When the exhaust pipe is cold, water vapor will condense as the exhaust cools on the pipe. After the pipe heats up, the vapor will not condense. Remember that the combustion of hydrocarbon fuel produces both carbon dioxide AND water vapor as a normal part of the process. All gasoline engines produce water vapor and all water vapor condenses if the exhaust pipe is cool.
Water coming out the tailpipe means there is water in the exhaust. This is not uncommon when the engine is cold and the exhaust is condensing. That situation should stop when the engine warms up. If the exhaust continues to have water in it after the engine is warmed up it could possibly indicate a leaky head gasket or cracked cylinder head.