If your vehicle is showing excessive water dripping or sputtering from the muffler, here are the most likely causes and the parts you'll need to fix each one.
Water vapor is a natural byproduct of burning fuel. On cold starts, this vapor condenses in the cold exhaust piping and drips out of the muffler's designed weep hole until the system reaches operating temperature.
Frequent short trips prevent the exhaust from getting hot enough to evaporate normal condensation. This causes water to pool inside the muffler, which sputters out during hard acceleration and can eventually rust the exhaust from the inside out.
A failed head gasket allows engine coolant to leak into the combustion chamber. The engine burns the coolant, resulting in excessive water dripping and thick white, sweet-smelling steam exiting the muffler.
On some engine designs, a degraded intake manifold gasket can allow coolant to cross over into the intake runners, where it is burned and expelled as water and steam through the exhaust.
Severe overheating or freezing temperatures (without proper antifreeze) can crack the cylinder head or block, allowing large amounts of coolant to pour into the cylinders and out the exhaust.