Snake in the shower

I'm having a shower and I see what looks like a stick in the drain. Upon closer inspection I saw a snake. My housemate chased it back down with a plug and we plugged it up. Scary stuff. I'm now in the process of identifying the snake. My house mate thinks it's a poisonous one. My counterpart tells me that its unlikely to be poisonous as ones living in wet humid conditions generally are not.