Smelly water under the floor

kurochan

Could someone help us please?

The new kitchen was installed 4 months ago. We noticed some bad smell from the bathroom next to the kitchen about 2 months ago. We did all sorts of things for the smell, but it did not go. A plumber was called and found that the sink in the kitchen was connected to the wrong pipe that could be ending somewhere under the kitchen. Last week, we lift the floor board in the bathroom and found smelly water (2cm in depth) under the bath. It looks the water is coming from the Kitchen.

The plumber installed new drain pipes for the sink. We are really worried about the water under the floor, but he said it will dry out. However, we can still smell after 1 week. We looked at the water level from the bathroom, and it was decreasing though. Somebody said to us that we should lift the kitchen floor (brand new) and clean and dis-infect the ground underneath.

Our question is do we need to clean the ground under the kitchen? and if so, how can we do it? Is there a specialist for this kind of problem? Please give us your advice.