It's according to which ones, but most likely no. Just look at it, and you'll see what you have to do. It's best to wait until it throws a code, so you'll know which one to remove. When mine got wet it didn't go away. I drove for an hour or 2 with it missing. I finally had to take it out and dry it out. The COP was fine (no cracks) but it had water under the boot. I dried it out, and it was fine.

Edit: This is a really good idea, but only blow around the one that is giving you problems. You could try spraying it with wd 40 too. It won't hurt anything.

 

I've went through this twice, most recently a couple weeks ago.

When I first picked up the truck the dealer detailed the engine bay which caused the spark plug channels to get wet. That went away on it's own.

But more recently we got alot of rain and I discovered water was finding its way past the weather stripping and ending up in the spark plug holes. I went ahead and replaced all the COPs since I was at 85K miles. Then I liberally applied silicone sealant over the weather stripping and so far so good with the rain we had today.

If you do end up replacing your COPs, use lots of dielectric grease and make sure water doesn't end up on them. Shut your hood and spray water on your hood and windshield. If you've got a leak it'll be obvious which areas you want to address.