Do I need to water my artificial grass?

Do I need to water my artificial grass regularly, like once every 2 weeks, or once a month?

One of the biggest advantages artificial grass has over real grass is it will save water! 60% of a regular household's water bill goes to real grass lawns, by having artificial grass, you will stop wasting money on water bills along with a lot of environmental benefits.
To answer your question, No, you don't need to water your artificial grass at all. From time to time, you might need to clean your artificial grass lawns by using your garden hose to spray it down, but such water usage can be very minimum compared to the water consumptions of real grass lawns.

That's good to hear. I thought I have to water the artificial grass at least once a month so it will look fresh.

That is nice! Synthetic grass does not just save water consumption but my money and time too.