I think you'll want to have something small-ish that holds water. I don't think it needs to be a 'baby bath'. We bathed our daughter in a washing up bowl for probably the first month or so, and then switched to using a baby bath up until maybe 8 or 9 months. I think you absolutely can just use your regular bath, but if you pay for your water usage (on a meter), you'll definitely waste a lot of water. It definitely saved on water to use something smaller until she was big enough to sit up in the regular bath on her own. But it doesn't have to be a 'baby bath' per se. A large bucket would work fine, or a washing up bowl, or whatever.