How do i use drain out bathroom for maintenance and prevention purposes? Blocked sewer and storm water drains –. It goes without saying that if you try all of this and nothing works, you may need to call a plumber but why not try it yourself first? Fmb insurance services (registered number ) is a wholly-owned subsidiary of the fmb. We use reporting software and tools provided by wincan, industry leaders in regulation-compliant drainage surveys these are legally recognised.