Can't help you with access but maybe TAG could give you some pointers. So are you sure you have ONE problem and not two, meaning the light flow coming out is an issue and water in the bilge could be from a sump pump issue, perhaps the shower head needs to be descaled and your sump pump isn't working? Good pressure at other faucets? Or can you hear water spraying around the shower wall, I'd think if a hose were busted you might be able to hear the noise.