After excavating in my basement to put in a bathroom, there is now a pool of water in the hole. I am going to have a plumber put in the sewage and piping but he told me that there is a foundation problem because of the pool of water. There is no leaks in my basement and I am wondering if he is jacking up the price. Is this normal after digging down in the basement to have water pool in the hole or is he being honest?
There is no way for us to know that.
If the basement is below your water table, water could be seeping up into the excavation naturally, or there could be a nearby underground water supply line leaking or a drain line leaking (if it smells bad).
You will need permits and inspections for this work in any case, so you may want to have your Building Inspector come out to take a look, or get another plumber or contractor out for a second opinion.