1 sentence for 水 (shuǐ — extra income)

1. 去那个摊位兑换外币要收两分水。

   qù nà gè tān​wèi duì​huàn wài​bì yào shōu liǎng fēn shuǐ.

   Changing foreign currency at that stall costs a two percent commission.

   Source: Dong Chinese Dictionary