Not much. Polk was out of DC for around 3 months before he died, so it's unlikely that the DC water was the culprit. He most likely picked up cholera during a trip to New Orleans. He was around several confirmed cases of it, includingone confirmed case that he was in direct contact with. It's explained in his biography by walter borneman. Polk, the man who transformed the presidency. The title may be different. It's close to that though.

The other two...

it's generally accepted (now) that Harrison's death was from a combination of typhoid or paratyphoid, which is not the same as typhus, and medical treatment failure by giving him meds that made his condition worse. Sources - There are a lot of medical studies published about this one. I am a former epidemiologist turned historian. Because of the history interest I read a lot of 19th century disease cases when I was working in the field. Searching JSTOR, NEJM or even Google for Harrison's cause of death will give you a lot of choices.

Taylor... first, ignore all of the assassination conspiracy theories. Like Harrison, there's a ton of medical publications on this one too. JSTOR, NEJM and Google. The physicians for sure gave him way too much medication. Including heavy doses of laxatives and opium, which is an absolute disaster if you have a stomach ailment. No one really knows for sure, but it's generally accepted that he had some sort of stomach virus or a bacterial infection. Several of his staff members had the same symptoms that he did, but lived. Most likely it was cholera morbus, which is just an old slang term for gastroenteritis and poor judgment by his doctors. His death events were very similar to Harrison.

There's no way to really prove or disprove Taylor or Harrison to the water supply because it was like 150-ish years ago and there's not really solid evidence of either having cholera, but Polk is a hard no. The water was putrid though, so regardless of what happened, it couldn't have helped.