We have a horrible smell coming from our drains and now there is water leaking from the pipes in the walls behind our kitchen sink out to the front porch. There is black in the water and it has a horrible boiled egg type smell. Anytime we use any water it leaks on the porch. We do not have a foundation but a slab instead. this morning we noticed the water leak was there even though we had not used the dish washer or sink. the same smell is coming from a huge hole that was put beside our airconditioning and heater in the closet before we moved in 9 years ago. We have been told we probably have a break in the pipes. What do you think?