Why did Jewish people start having two sinks?

Answer 1

Kosher regulations do not permit mixing milk dishes with meat dishes. This is why kosher kitchens have 2 sets of silverware, dishes etc., to keep from mixing. Two sinks is not strictly required but is usually the case in religious Jewish homes.

Answer 2

In Kashrut, Jewish foods laws, meat products and dairy products must be handled and consumed separately. Additionally, all dishes and cooking utensils must be segregated between meat and dairy use. Having two sinks allows one to be used for dairy and one to be used for meat.

Answer 3

Orthodox Jews usually have 2 sinks to keep meat and dairy separate at all times.