NEW ORLEANS -- We won't know if the water in New Orleans was contaminated until Thursday, but the danger it could pose is very real, especially if you're already sick.

Test results from the water samples taken around the parish usually take about 24 hours to process, but in the meantime, doctors say it's best to play it safe and there are some people who need to take more precautions than others.

The mother of an 18-month-old boy just learned about the boil water advisory in Orleans Parish hours after it was announced.

"So I texted my husband and said, 'No water for Graham. Let's just give him juice for the rest of the day and wait 'til this lifts," Nicole Davis said.

A "power fluctuation" caused a widespread drop in water pressure in New Orleans Wednesday morning.

According to Sewerage and Water Board officials, that drop in water pressure caused the city to issue a precautionary boil water advisory for the entire east bank of Orleans Parish.

"If you swallow water that's contaminated with certain types of bacteria, you can get gastrointestinal illnesses, vomiting, diarrhea for example," explained Dr. Fred Lopez, an infectious disease expert at LSU Health Sciences Center.

He says for healthy people, those intestinal problems will clear on their own. It's those with chronic health problems who especially need to boil water for at least a minute, or drink bottled water.

"This has some real health risks, particularly if you don't have an immune system that's working particularly well. You really want to stay away from the water until it's been cleared," Dr. Lopez advised.

He says healthy people will be fine taking a bath or shower, just make sure not to swallow water. Getting it in your eyes could cause a little irritation.

Use bottled water to brush your teeth and throw out ice. Freezing does not kill the potential bacteria. And those filters on your tap are not a guaranteed to remove those contaminants either.

Also, don't wash dishes or clean your counter tops using water. While most problems will clear up on their own for healthy people, those with healing wounds need to be extra careful.

"For example, you have an open wound, you can cause a wound infection," Dr. Lopez said.

That's something Melissa Carollo wants to avoid with her husband's six inch incision.

"The boil water advisory is going to be a little bit of a pain because my husband just had back surgery, so getting him showered now already is a little bit of a hassle, and I don't know how I'm going to get him showered boiling water," Carollo said.

Here is a fact sheet from the CDC with answers to all your questions during a boil water advisory: