Hi my 3 year old dog has started to pee in the house during the night.

Some nights she is fine but other mornings we wake up to a flood of pee.

What can we do?

Why does she manage some nights but not others?

We bleach/disinfect the floor but are not sure if this is completely moving the smell. What else can we use?

Thanks

You can take her to the veterinarian to rule out a kidney or urinary tract problem.  If that's not an issue then it's a behavioral problem that you can try to solve by re-housetraining her.