Whether you're visiting Seoul for the first time or are a local who lives in a large apartment complex, you should consider purchasing filtered water to drink in your kitchen. Filtered water jugs can be bought in stores or online for about 30,000 to 50,000 KRW, and are an eco-friendly choice. While a filter jug may seem like a luxury, it is more economical than buying bottled water and will reduce your water bill in the long run.