méiyǒu lòushuǐ yě méiyǒu rén qiāomén zhǐshì lóushàng yǒurén xǐwánzǎo guǎndào lǐ liúxià de yìdiǎn shēngyīn

没有漏水，也没有人敲门，只是楼上有人洗完澡，管道里留下的一点声音。

There is no leak and no one is knocking on the door; it's just some noise left in the pipes after someone upstairs finished taking a shower.