How to best encourage better bathroom usage?

I work in a company of about 15 people. Previously, we had an office in an office park, sharing bathroom facilities with three other businesses. So, the bathrooms were what you got.

Recently, our business moved into a new office, where everyone shares one single bathroom. It's obvious that one person (unknown) is leaving the bathroom in, uh, less than a pristine state. We sent out a memo regarding the new office facilities, alluding to leaving the bathroom in a good state; however, it's obvious that someone is clueless.

How can we get the message to the right individual that his/her bathroom habits are not pleasant for the rest of the office colleagues?

Idle threats.

You may want to try another very strongly worded memo. Outline in plain clear English what needs to be done after you have used the washroom, and simply state that we are all entitled to have a clean and functional facility. Outline that it is matter of respect for fellow staff.

When all else fails state that if the washroom cannot be left in neat, you will be forced to have put a lock on the door and have staff sign out a key.

I think it's best if you tell them if you don't know how to keep the bathroom right, then don't use the bathroom at all.

check the bathroom after everyone uses it to find out who it is than go from there...

At my old job I posted a memo calling the person a pig, she got offended, but she cleaned up after her self from than on ( I wouldn't suggest this though, it's not very nice )

When we were kids, for a Halloween joke, we would pud dung in a paper bag and set fire to it on someones porch....I know it is juvenile and corny. Might want to put a bagfulll of stuff on his desk with a note saying that you know he is the pig and you want him to stop.

Discourteous people will continue to be discourteous if you let them

I had the same problem so I walked over to the co-worker's desk and with a smile on my face (as if I were joking - but there is a seriousness to every joke)asked, "Geez, are you the one who keeps leaving the toilet seat up and water all over the place? I'd hate to see your bathroom at home." Then I walked away and never mentioned it again.

Post a sign in each stall of the bathroom to clean up after one's self and also on the door of the bathroom.

We have posted things in the restroom hinting at things like if you can't make the bowl at least clean it up, wash your hands, and courtesy flushing.

Every office has a dis-courteous SOB that does this to the restroom. Leaving notes, and writing letters doesn't do any good.

When I was younger and living at my parents house, we had a neighbor that walked his dog and let it dump a load right at the end of the driveway. One night, I picked it up; put it in a baggie, and left it in his mailbox, and he never let the dog go in our driveway again.

Now, I'm not saying anyone should go that far, but if you want, I can send you a baggie.