boiling water

I guess I'm really tired, because I just boiled a kettle of water to put in the fridge, and was going to boil another one (my kettle is small) to add to it, but instead after filling up the kettle the second time to boil, I just poured it straight into the bottle of already boiled water. Argh. Now, I can either take my chances or reboil the whole thing.

(In Korea, there's apparently not a dependable water treatment system, because you aren't supposed to drink the tap water. It's such a developed country, so it's strange to have to do that, but I obey! Most people have their own water coolers in their house, or they buy their water from the store, but I just boil it. It's easy for one person.)