If a dog drinks too much water then the dog could suffer from water intoxication which can be deadly if not treated.
However the dog would unlikely drink too much water as the dog knows when to stop drinking water before they get sick.
A dog will drink enough water until they are no longer thirsty and then drink some more water when they are thirsty again.
If the dog does happen to drink too much water and get water intoxication they will usually experience symptoms that include staggering/loss of coordination, lethargy, nausea, bloating, vomiting, dilated pupils, glazed eyes, light gum color, and excessive salivation.
In severe cases the dog with water intoxication there can also be difficulty breathing, collapse, loss of consciousness, seizures, coma, and death.
When you have a dog you should leave a bowl of water out for the dog all day.
The dog should always have access at all times through the day to clean fresh drinking water.
If the dog is outside then you may need to dump the water out and put fresh cool water in the bowl when it's hot outside.
The water can get hot and the dog won't drink it.
So make sure the dog always has access to fresh and cool, clean drinking water at all times.
If the dog is inside then you may put the water up at night especially if the dog is a puppy and not potty trained.
But during the day the dog should always have access to water all day so they can drink water when they need it to prevent them from becoming dehydrated.