You can take some bilge water and put it on some paper and let it dry. Or you can have a great chance for some nasty infection- like the MRSA I got while working at the yard from a visiting boat. The same MRSA that took out a heart valve so I had to have open heart surgery. Go ahead- taste all the bilge water you want; not me. Your mouth/teeth is the best way for infection to go directly to the bloodstream.
Last I heard you're a lot more likely to get MRSA in a hospital than in a bilge. Even the odds of finding holding tank residuals are pretty remote, and...well I won't go there. Most likely the worst you'll find is a little anti-freeze, oil or soapy water. And we're talking about a lick of a finger tip, not filling a water glass and drinking. With the condition of the world you think I'm going to sweat every possibility? I have a garage and a car with a key and exhaust pipe for those things. Put it on paper and let it dry to determine if it's rainwater or saltwater? And what, tell the owner I'll let him know in a couple of hours if it's safe to cruise? What kind of a woos world have we created. I know you had MRSA and it's a horrible disease, but live free or die. Conducting my life in fear is unacceptable to me.
checking the contents of the bilge below the forward passageway will usually show sewage on those 50 Posts as the holding tank, hoses and thru' hull are all in that low area and the hose clamps are sitting in the water that the submersible pump can not pump out. On the early 50's the holding tank did not have a macerator discharge pump but used gravity by opening the thru' hull valve while under way (3 miles off shore obviously) and letting gravity and the suction effect below the boat to suck it out. Later models had a pump installed. It is very common to find rusty and broken hose clamps on the head hoses in these bilges and leaking sewage. I would rather have tasted the engine room bilges as I could live with oil or diesel in my system but the thought of sh1t kind of puts me off, in fact these days I do not taste anything in any bilges, sumps or tanks. There are expandable rubber plugs throughout the bilges in the limber holes on all Posts and if these are in place they create partial water tight bulkheads.
Hearing has slipped a little from being wasted listening to too many people with nothing to say mumble (and a few too many engine rooms), but otherwise all still good. And a good imune system because I haven't tried to hide from every germ in creation.
Back to the OP's orginal problem, FWhaughten, did you ever find out if your showers were dumping directly into the bilge or your sump pump wasn't working??
I know all about this situation on these 50' Posts.......Also, if you forget one of these gravity drains open, or one of the direct overboard valves, the wonderful holding tank backfills itself.......
Experience keeps a dear school. My bills for the MRSA that year were over half a million dollars in health costs alone- not to mention lost work and nearly dieing twice. I try to not do things that can kill me if I don't have to, especially when the thing is minor. On the left hand- put a few drops of water on a piece of paper and use a heat gun for a minute, or one the right hand taste the water and have a chance to die or drink sh!t- and if you want to choose ingesting bilge water with the unknown contents, great. What does the owner say when you tell them you tasted the bilge water? Most will look at you like your crazy- as I would.
You bring a heat gun on board with you while moving boats and carry it while doing engine room checks? I'd think that would raise an eyebrow or two. Maybe you should take a sample and send it to a lab, wait for the results and then take the boat out. Oops, it might have rained or the boat may have been washed before the results came in. Better do it again and tell the owner to wait a few more weeks before you take the boat out. 55 years on the water, drank out of lawn hoses, and have never sweated the small stuff. No alargies, totally healthy, strong as most 40 year olds and can also out-work most of them. I watch all the antiseptic people of the last couple of generations avoiding peanuts and constantly using Purell and antiseptic sprays. They eat one peanut or get exposed to one germ and they're down for the count. You're been watching too many commercials and believing the advertising. P&G loves you.
I have a heat gun on board all the time. I do engine room check both before I leave the slip and while underway. Your response sounds as if you only do them while the boat is underway- but I'm sure that is not really what you do. Again- if the boat is at the slip it take all of 2 minutes to check the water, about the same amount of time underway. If the boat is rocking so much inside the engine room I cannot do this underway then I should have never gone out in the first place. Would you like the step by step instructions? Love me? Why? I have no phobia as you describe. I have proof that boats can carry MRSA and tasting bilge water can kill you. I used to have your attitude until I nearly died twice; as I said- experience keeps a dear school. I doubt anything I or someone else says will change your mind as evidenced by your condescending tone. I usually perk up and listen when another professional mariner tells me something I'm doing could kill me. I'm surprised with your aversion to a easy solution.
Not meant to be condescending. I've been reading your posts for quite awhile now, and have the utmost respect for you. Sarcastic though, maybe. That's the Irish in me. If I find water underway, there's no need to taste it. It's obviously a problem. There's basicly 3 places to check: bilge for salt, pipes and hoses for fresh or waste, and the color and odor will give you a hint of which. 5 senses. I use taste when there's no odor or color, at the dock, when it's more likely than not that you're dealing with rain or wash water. I sure don't go bobbing for hersey bars. I've been on very few smaller boats (except workboats) that carried a heat gun, and as an independent captain I carry enough gear. But I do carry Atomic and electrical tape for emergency repairs.