Kitchen
A quiet dishwasher leak often shows up downstairs first.
A supply, drain, or door-seal failure can wet the cabinet, the floor, and then the suite below. The kitchen may look almost dry while the ceiling downstairs is not.
Stop the cycle and close the supply.
Cancel the wash. Close the dishwasher stop under the sink if it is labelled and dry enough to reach. Do not keep restarting the machine to watch it drip.
Check the cabinet and the suite below together.
Look for wet kick plates, swollen particle board, and a cold spot on the floor. Ask whether the unit below saw water during the same cycle.
Drain line versus supply line.
A supply leak can run constantly. A drain leak often follows a wash. That difference helps an investigator, so write it down before the cabinet is torn out.
Questions people ask
Is the installation always at fault?
Not always. A hose, a fitting, a clogged air gap, or a failing tub can each leak. The finding should name the part, not the brand of blame.
Can I use the kitchen sink in the meantime?
Only if that supply is separate and dry. If the cabinet is wet, leave the area and get the building involved.