Dripping Sound Under Floor
First check your basement or crawl space below the spot where you hear the water sound.
Dripping sound under floor. The drip drip drip goes on for maybe an hour. A water leak inside a wall can destroy wallboard and insulation and lead to mold or mildew problems. The sound is from a very area in the ceiling around 1ft radius circle. Although it may sound minor this leak causes major damage when water seeps into the subfloor where flooring meets the tub or shower.
From there i can hear the dripping but can see no water leaking anywhere. Interesting i noticed every time someone is talking shower on the second floor guest bath right below it on the first floor i could hear dripping or ticking sound. Gramp ca after flushing an upstairs toilet i can hear a dripping sound in the first floor room underneath that bathroom. Fortunately not every water sound signals a problem sometimes the water is safely inside pipes.
The conclusion is assumed to be a leak under the floor. Listen carefully for this noise because if you detect it it can lead you right to the source of the leak. Leaking pipes often project a strange hollow hissing sound. After shutting off the water on the second floor the sound finally tapers off after 5 10 min.
Even worse the plywood subfloor delaminates and rots requiring a huge expensive tearout and replacement project. Be sure to especially check the kitchen as there are many water sources and water pipes in that room. I crawled under the house where i can eyeball the toilet drain pipe.